diff --git a/README.md b/README.md
index 9d4e836..b806099 100644
--- a/README.md
+++ b/README.md
@@ -95,6 +95,10 @@ client.project(project_id).stories(fields: ':default,tasks')              # Eage
 story.comments(fields: ':default,person')                                 # Eagerly get comments and the person that made the comment for a story
 ```
 
+## Error Handling
+`TrackerApi::Errors::ClientError` is raised for 4xx HTTP status codes  
+`TrackerApi::Errors::ServerError` is raised for 5xx HTTP status codes
+
 ## Warning
 
 Direct mutation of an attribute value skips coercion and dirty tracking. Please use direct assignment or the specialized add_* methods to get expected behavior.
@@ -118,6 +122,7 @@ story.save
 
 - Add missing resources and endpoints
 - Add create, update, delete for resources
+- Error handling for [error responses](https://www.pivotaltracker.com/help/api#Error_Responses)
 
 ## Semantic Versioning
 http://semver.org/
diff --git a/lib/tracker_api.rb b/lib/tracker_api.rb
index 3191fec..9a4f850 100644
--- a/lib/tracker_api.rb
+++ b/lib/tracker_api.rb
@@ -29,6 +29,8 @@ module TrackerApi
 
   module Errors
     class UnexpectedData < StandardError; end
+    class ClientError < Error; end
+    class ServerError < Error; end
   end
 
   module Endpoints
diff --git a/lib/tracker_api/client.rb b/lib/tracker_api/client.rb
index c092451..f182e5a 100644
--- a/lib/tracker_api/client.rb
+++ b/lib/tracker_api/client.rb
@@ -248,7 +248,11 @@ def request(method, options = {})
       end
       response
     rescue Faraday::Error::ClientError => e
-      raise TrackerApi::Error.new(e)
+      case e.response[:status]
+      when 400..499 then raise TrackerApi::Errors::ClientError.new(e)
+      when 500..599 then raise TrackerApi::Errors::ServerError.new(e)
+      else raise "Expected 4xx or 5xx HTTP status code"
+      end
     end
 
     class Pagination
diff --git a/test/error_test.rb b/test/error_test.rb
new file mode 100644
index 0000000..ac46ddf
--- /dev/null
+++ b/test/error_test.rb
@@ -0,0 +1,41 @@
+require_relative 'minitest_helper'
+
+describe TrackerApi::Error do
+  let(:pt_user) { PT_USER_1 }
+  let(:client) { TrackerApi::Client.new token: pt_user[:token] }
+  let(:options) { { url: nil, headers: nil } }
+
+  it 'raises ClientError for 4xx HTTP status codes' do
+    (400..499).each do |status_code|
+      mock_faraday_error(status_code)
+      assert_raises TrackerApi::Errors::ClientError do
+        client.send(:request, :get, options)
+      end
+    end
+  end
+
+  it 'raises ServerError for 5xx HTTP status codes' do
+    (500..599).each do |status_code|
+      mock_faraday_error(status_code)
+      assert_raises TrackerApi::Errors::ServerError do
+        client.send(:request, :get, options)
+      end
+    end
+  end
+  
+  it 'raises RuntimeError for HTTP status codes < 400 and > 500' do
+    [399, 600].each do |status_code|
+      mock_faraday_error(status_code)
+      assert_raises RuntimeError, "Expected 4xx or 5xx HTTP status code" do
+        client.send(:request, :get, options)
+      end
+    end
+  end
+
+  # Simulate the error Faraday will raise with a specific HTTP status code so
+  # we can test our rescuing of those errors
+  def mock_faraday_error(status_code)
+    ::Faraday::Connection.any_instance.stubs(:get).
+      raises(::Faraday::Error::ClientError.new(nil, { status: status_code}))
+  end
+end