diff --git a/app/controllers/sessions_controller.rb b/app/controllers/sessions_controller.rb
index 1828b78..f5c93a4 100644
--- a/app/controllers/sessions_controller.rb
+++ b/app/controllers/sessions_controller.rb
@@ -23,6 +23,8 @@ def create
         omniauth_uid:      auth['uid']
       ).first || User.create_with_omniauth(auth)
 
+      user.update!(email: auth['info']['email'])
+
       session[:user_id] = user.id
       return redirect_to params[:return_to] if params[:return_to].present?
     end
diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 497ff67..ee94012 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -1,5 +1,7 @@
 # -*- encoding : utf-8 -*-
 require 'kramdown'
+require 'digest/md5'
+require 'uri'
 
 module ApplicationHelper
 
@@ -51,4 +53,25 @@ def markdown(md_body)
       md_body
     end
   end
+
+  def gravatar_image(user, options = {})
+    return nil if user.nil? || user.email.nil?
+
+    hash = Digest::MD5.hexdigest(user.email.downcase)
+    query = options.select { |k, v| [:size, :default].include?(k) }
+                   .map { |k, v| "#{k}=#{URI.encode(v.to_s)}" }
+                   .join('&')
+    src = "//www.gravatar.com/avatar/#{hash}?#{query}"
+
+    img_options = { :alt => user.nickname }
+    if mouseover = options[:mouseover]
+      img_options = mouseover
+    end
+    if size = options[:size]
+      img_options[:width] = size
+      img_options[:height] = size
+    end
+
+    image_tag(src, img_options)
+  end
 end
diff --git a/app/models/user.rb b/app/models/user.rb
index b56b58e..11cfbe6 100644
--- a/app/models/user.rb
+++ b/app/models/user.rb
@@ -11,6 +11,7 @@ def self.create_with_omniauth(auth)
     create! do |user|
       user.omniauth_provider = auth['provider']
       user.omniauth_uid = auth['uid']
+      user.email = auth['info']['email']
       user.nickname = nil
     end
   end
diff --git a/app/views/gists/_fork_of.html.erb b/app/views/gists/_fork_of.html.erb
index db2fb5c..4f33455 100644
--- a/app/views/gists/_fork_of.html.erb
+++ b/app/views/gists/_fork_of.html.erb
@@ -10,7 +10,9 @@
           <%= time_ago_in_words(@gist.source_gist.created_at) + ' ago' %>
           by
           <% if @gist.source_gist.user.nil? %>Anonymous
-              <% else %><%= link_to @gist.source_gist.user.nickname, user_path(@gist.source_gist.user) %>
+          <% else %>
+            <%= link_to @gist.source_gist.user.nickname, user_path(@gist.source_gist.user) %>
+            <%= gravatar_image(@gist.source_gist.user, :size => 15) %>
           <% end %>
         </small>
       </li>
diff --git a/app/views/gists/_forks.html.erb b/app/views/gists/_forks.html.erb
index 213dac4..bbc786e 100644
--- a/app/views/gists/_forks.html.erb
+++ b/app/views/gists/_forks.html.erb
@@ -11,7 +11,9 @@
               <%= time_ago_in_words(gist.created_at) + ' ago' %>
               by
               <% if gist.user.nil? %>Anonymous
-                  <% else %><%= link_to gist.user.nickname, user_path(gist.user) %>
+              <% else %>
+                <%= link_to gist.user.nickname, user_path(gist.user) %>
+                <%= gravatar_image(gist.user, :size => 15) %>
               <% end %>
             </small>
           </li>
diff --git a/app/views/gists/_history.html.erb b/app/views/gists/_history.html.erb
index 4d4750b..64ca022 100644
--- a/app/views/gists/_history.html.erb
+++ b/app/views/gists/_history.html.erb
@@ -8,13 +8,17 @@
               <%= time_ago_in_words(history.created_at) + ' ago' %>
               by
               <% if history.user.nil? %>Anonymous
-                  <% else %><%= link_to history.user.nickname, user_path(history.user) %>
+              <% else %>
+                <%= link_to history.user.nickname, user_path(history.user) %>
+                <%= gravatar_image(history.user, :size => 15) %>
               <% end %>
           <% else %>
               <%= link_to time_ago_in_words(history.created_at) + ' ago', show_history_gist_path(@gist, history) %>
               by
               <% if history.user.nil? %>Anonymous
-                  <% else %><%= link_to history.user.nickname, user_path(history.user) %>
+              <% else %>
+                <%= link_to history.user.nickname, user_path(history.user) %>
+                <%= gravatar_image(history.user, :size => 15) %>
               <% end %>
           <% end %>
         </small>
diff --git a/app/views/gists/_list.html.erb b/app/views/gists/_list.html.erb
index 5a630e9..b758859 100644
--- a/app/views/gists/_list.html.erb
+++ b/app/views/gists/_list.html.erb
@@ -20,6 +20,7 @@
                     Anonymous
                 <% else %>
                     <%= link_to gist.user.nickname, user_path(gist.user) %>
+                    <%= gravatar_image(gist.user, :size => 20) %>
                 <% end %>
               </small>
             </div>
diff --git a/app/views/root/index.html.erb b/app/views/root/index.html.erb
index 2f04b05..4fbc595 100644
--- a/app/views/root/index.html.erb
+++ b/app/views/root/index.html.erb
@@ -22,7 +22,9 @@
                   <%= time_ago_in_words(gist.latest_history.created_at) + ' ago' %>
                   by
                   <% if gist.user.nil? %>Anonymous
-                      <% else %><%= link_to gist.user.nickname, user_path(gist.user) %>
+                  <% else %>
+                    <%= link_to gist.user.nickname, user_path(gist.user) %>
+                    <%= gravatar_image(gist.user, :size => 20) %>
                   <% end %>
                 </small>
               </div>
diff --git a/app/views/users/show.html.erb b/app/views/users/show.html.erb
index a66ecac..d3bf513 100644
--- a/app/views/users/show.html.erb
+++ b/app/views/users/show.html.erb
@@ -2,7 +2,10 @@
 
   <%= render :partial => 'common/flash_notice' %>
 
-  <h2><%= @user.nickname %></h2>
+  <h2>
+    <%= gravatar_image(@user, :size => 30) %>
+    <%= @user.nickname %>
+  </h2>
   <hr/>
 
   <table class="table table-bordered">
@@ -12,6 +15,9 @@
     <tr>
       <td><%= @user.omniauth_uid %></td>
     </tr>
+    <tr>
+      <td><%= @user.email %></td>
+    </tr>
   </table>
 
   <% if @user.id == current_user.try(:id) %>
diff --git a/db/migrate/20140110041301_add_email_to_users.rb b/db/migrate/20140110041301_add_email_to_users.rb
new file mode 100644
index 0000000..1370f7d
--- /dev/null
+++ b/db/migrate/20140110041301_add_email_to_users.rb
@@ -0,0 +1,5 @@
+class AddEmailToUsers < ActiveRecord::Migration
+  def change
+    add_column :users, :email, :string
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 2c01257..8cd1add 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,36 +11,36 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20121015023421) do
+ActiveRecord::Schema.define(version: 20140110041301) do
 
   create_table "comments", force: true do |t|
     t.integer  "gist_id",    null: false
     t.integer  "user_id",    null: false
     t.text     "body",       null: false
-    t.datetime "created_at"
-    t.datetime "updated_at"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
   end
 
   create_table "favorites", force: true do |t|
     t.integer  "user_id",    null: false
     t.integer  "gist_id",    null: false
-    t.datetime "created_at"
-    t.datetime "updated_at"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
   end
 
   create_table "gist_files", force: true do |t|
     t.string   "name",            null: false
     t.text     "body",            null: false
     t.integer  "gist_history_id", null: false
-    t.datetime "created_at"
-    t.datetime "updated_at"
+    t.datetime "created_at",      null: false
+    t.datetime "updated_at",      null: false
   end
 
   create_table "gist_histories", force: true do |t|
     t.integer  "gist_id",    null: false
     t.integer  "user_id"
-    t.datetime "created_at"
-    t.datetime "updated_at"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
   end
 
   create_table "gists", force: true do |t|
@@ -48,16 +48,17 @@
     t.boolean  "is_public",      null: false
     t.integer  "user_id"
     t.integer  "source_gist_id"
-    t.datetime "created_at"
-    t.datetime "updated_at"
+    t.datetime "created_at",     null: false
+    t.datetime "updated_at",     null: false
   end
 
   create_table "users", force: true do |t|
     t.string   "nickname"
     t.string   "omniauth_provider", null: false
     t.string   "omniauth_uid",      null: false
-    t.datetime "created_at"
-    t.datetime "updated_at"
+    t.datetime "created_at",        null: false
+    t.datetime "updated_at",        null: false
+    t.string   "email"
   end
 
 end
diff --git a/spec/controllers/sessions_controller_spec.rb b/spec/controllers/sessions_controller_spec.rb
index e99a341..51faf9b 100644
--- a/spec/controllers/sessions_controller_spec.rb
+++ b/spec/controllers/sessions_controller_spec.rb
@@ -25,18 +25,35 @@ def valid_session
 
   describe "GET /auth/:provider/callback" do
     it "accepts requests without header" do
-      get :create, {:provider => 'open_id'}, valid_session
+      get :create, {:provider => 'open_id'}
       expect(response.status).to eq(302)
       expect(response).to redirect_to root_path
     end
-    it "accepts requests" do
-      request.env['omniauth.auth'] = {
-          "provider" => 'open_id',
-          "uid" => "xxx"
-      }
-      get :create, {:provider => 'open_id', :return_to => '/foo'}, valid_session
-      expect(response.status).to eq(302)
-      expect(response).to redirect_to 'http://test.host/foo'
+    it "creates new user" do
+      expect {
+        request.env['omniauth.auth'] = {
+          'provider' => 'open_id',
+          'uid' => 'yyy',
+          'info' => { 'email' => 'test@test.org' }
+        }
+        get :create, {:provider => 'open_id'}
+      }.to change { User.count }.from(0).to(1)
+      u = User.first
+      expect(u.omniauth_provider).to eq('open_id')
+      expect(u.omniauth_uid).to eq('yyy')
+      expect(u.email).to eq('test@test.org')
+    end
+    it "updates existing user" do
+      expect {
+        request.env['omniauth.auth'] = {
+          'provider' => user.omniauth_provider,
+          'uid' => user.omniauth_uid,
+          'info' => { 'email' => 'test@test.org' }
+        }
+        get :create, {:provider => user.omniauth_provider}
+      }.not_to change { User.count }.from(1)
+      user.reload
+      expect(user.email).to eq('test@test.org')
     end
   end
 
diff --git a/spec/models/user_spec.rb b/spec/models/user_spec.rb
index f7611c5..f97abb4 100644
--- a/spec/models/user_spec.rb
+++ b/spec/models/user_spec.rb
@@ -8,14 +8,31 @@
     expect(user).not_to be_nil
   end
 
-  it 'create with omniauth' do
+  it 'create with omniauth without email' do
     auth = {
-        "provider" => 'open_id',
-        "uid" => 'xxxxxx'
+        'provider' => 'open_id',
+        'uid' => 'xxxxxx',
+        'info' => {}
     }
     created = User.create_with_omniauth(auth)
     expect(created.omniauth_provider).to eq('open_id')
     expect(created.omniauth_uid).to eq('xxxxxx')
+    expect(created.email).to be_nil
+    expect(created.nickname).to be_nil
+  end
+
+  it 'create with omniauth with email' do
+    auth = {
+        'provider' => 'open_id',
+        'uid' => 'xxxxxx',
+        'info' => {
+          'email' => 'test@test.org'
+        }
+    }
+    created = User.create_with_omniauth(auth)
+    expect(created.omniauth_provider).to eq('open_id')
+    expect(created.omniauth_uid).to eq('xxxxxx')
+    expect(created.email).to eq('test@test.org')
     expect(created.nickname).to be_nil
   end
 
diff --git a/spec/requests/gists_spec.rb b/spec/requests/gists_spec.rb
index 2e0fd60..203e977 100644
--- a/spec/requests/gists_spec.rb
+++ b/spec/requests/gists_spec.rb
@@ -5,6 +5,9 @@
 
   describe "GET /gists" do
     it "works" do
+      3.times do
+        create(:gist)
+      end
       get gists_path
       expect(response.status).to be(200)
     end