diff --git a/HISTORY b/HISTORY
index d7fdc8b..e157c05 100644
--- a/HISTORY
+++ b/HISTORY
@@ -10,6 +10,7 @@ JSLintMate
   TextMate 2.
 * FIX: Added unused variable warnings (if the option is enabled) to the quick
   mode tooltip.
+* FIX: Differentiated default `undef` settings for JSLint and JSHint.
 
 
 1.3 (2012-03-05)
diff --git a/Support/lib/jslintmate.rb b/Support/lib/jslintmate.rb
index da0e77b..fdab9ea 100644
--- a/Support/lib/jslintmate.rb
+++ b/Support/lib/jslintmate.rb
@@ -23,7 +23,7 @@
 #   2.  Options file (via `TM_JSLINTMATE_JSLINT_OPTIONS_FILE` or
 #       `TM_JSLINTMATE_JSHINT_OPTIONS_FILE`)
 #   3.  [deprecated] Custom bundle preferences (via `--linter-options`)
-#   4.  Default bundle preferences (via `JSLintMate::Linter.default_options`)
+#   4.  Default bundle preferences (via `JSLintMate::Linter#default_options`)
 #
 # To update jslint.js and jshint.js:
 #
diff --git a/Support/lib/jslintmate/linter.rb b/Support/lib/jslintmate/linter.rb
index 60a5fca..a91e956 100644
--- a/Support/lib/jslintmate/linter.rb
+++ b/Support/lib/jslintmate/linter.rb
@@ -6,11 +6,12 @@ module JSLintMate
   class Linter
     include OptionsFiles
 
-    # Use `default_options` instead of `DEFAULT_OPTIONS`.
+    # Use `default_options` instead of `DEFAULT_OPTIONS`. See also `jslint.json`
+    # and `jshint.json`.
     DEFAULT_OPTIONS = {
-      'undef' => false  # `true` if variables and functions need not be
-                        # declared before use.
-    }
+      :jslint => { 'undef' => false },
+      :jshint => { 'undef' => true }
+    }.freeze
     JSC_PATH          = '/System/Library/Frameworks/' <<
                         'JavaScriptCore.framework/Versions/A/Resources/jsc'
     LINT_REGEXP       = /^(Lint at line )(\d+)(.+?:)(.+?)\n(?:(.+?))?$/
@@ -34,11 +35,6 @@ class Linter
 
     ### Class methods ###
 
-    def self.default_options
-      # Returns a hash representation of `DEFAULT_OPTIONS`.
-      @default_options ||= options_hash_to_string(DEFAULT_OPTIONS)
-    end
-
     def self.runner_path
       @runner_path ||= JSLintMate.lib_path('runner.js')
     end
@@ -109,15 +105,20 @@ def initialize(key, attrs={})
 
     def to_s; name; end
 
+    def default_options
+      @default_options ||= DEFAULT_OPTIONS[key]
+    end
+
     def default_path
       JSLintMate.lib_path("#{key}.js")
     end
 
     def runner_command(filepath)
       runner_path = JSLintMate::Linter.runner_path
+      default_options_string = Linter.options_hash_to_string(default_options)
 
       runner_options = {
-        '--linter-options-from-defaults'     => Linter.default_options,
+        '--linter-options-from-defaults'     => default_options_string,
         '--linter-options-from-bundle'       => options_from_bundle,
         '--linter-options-from-options-file' => options_from_options_file
       }