diff --git a/NEWS b/NEWS
index 5a3dfdfa..327bee30 100644
--- a/NEWS
+++ b/NEWS
@@ -15,6 +15,7 @@ NEWS ( CHANGELOG and HISTORY )                                     HTMLPurifier
 - AttrValidator operations are now atomic; updates to attributes are not
   manifest in token until end of operations. This prevents naughty internal
   code from directly modifying CurrentToken when they're not supposed to.
+- Percent encoding checks enabled for URI query and fragment
 . Added HTMLPurifier_UnitConverter and HTMLPurifier_Length for convenient
   handling of CSS-style lengths. HTMLPurifier_AttrDef_CSS_Length now uses
   this class.
diff --git a/TODO b/TODO
index a7f3736a..ad5e080d 100644
--- a/TODO
+++ b/TODO
@@ -11,7 +11,6 @@ If no interest is expressed for a feature that may require a considerable
 amount of effort to implement, it may get endlessly delayed. Do not be
 afraid to cast your vote for the next feature to be implemented!
 
-- Implement validation for query and for fragment
 - Ability to fully turn off imagecrash fixes (attribute and CSS will require
   two separate directives due to our architecture.)
 - Investigate how early internal structures can be accessed; this would
diff --git a/library/HTMLPurifier/URI.php b/library/HTMLPurifier/URI.php
index 43f1b192..cab09bfb 100644
--- a/library/HTMLPurifier/URI.php
+++ b/library/HTMLPurifier/URI.php
@@ -128,6 +128,17 @@ class HTMLPurifier_URI
             $this->path = ''; // just to be safe
         }
         
+        // qf = query and fragment
+        $qf_encoder = new HTMLPurifier_PercentEncoder($chars_pchar . '/?');
+        
+        if (!is_null($this->query)) {
+            $this->query = $qf_encoder->encode($this->query);
+        }
+        
+        if (!is_null($this->fragment)) {
+            $this->fragment = $qf_encoder->encode($this->fragment);
+        }
+        
         return true;
         
     }
diff --git a/tests/HTMLPurifier/URITest.php b/tests/HTMLPurifier/URITest.php
index 97d77927..b4e99413 100644
--- a/tests/HTMLPurifier/URITest.php
+++ b/tests/HTMLPurifier/URITest.php
@@ -184,6 +184,14 @@ class HTMLPurifier_URITest extends HTMLPurifier_URIHarness
         $this->assertValidation("\xE3\x91\x94", '%E3%91%94');
     }
     
+    function test_validate_query() {
+        $this->assertValidation("?/\xE3\x91\x94", '?/%E3%91%94');
+    }
+    
+    function test_validate_fragment() {
+        $this->assertValidation("#/\xE3\x91\x94", '#/%E3%91%94');
+    }
+    
     function test_validate_path_empty() {
         $this->assertValidation('http://google.com');
     }