diff --git a/NEWS b/NEWS
index 576365ed..7fdc3e0a 100644
--- a/NEWS
+++ b/NEWS
@@ -18,6 +18,9 @@ NEWS ( CHANGELOG and HISTORY )                                     HTMLPurifier
 ! Full PHP 7 compatibility, the test suite is ALL GO.
 ! %CSS.AllowDuplicates permits duplicate CSS properties.
 ! Support for 'tel' URIs.
+! Partial support for 'border-radius' properties when %CSS.AllowProprietary is true.
+  The slash syntax, i.e., 'border-radius: 2em 1em 4em / 0.5em 3em' is not
+  yet supported.
 - alt truncation could result in malformed UTF-8 sequence. Don't
   truncate.  Thanks Brandon Farber for reporting.
 - Linkify regex is smarter, based off of Gruber's regex.
diff --git a/configdoc/usage.xml b/configdoc/usage.xml
index d3856974..b4d0d863 100644
--- a/configdoc/usage.xml
+++ b/configdoc/usage.xml
@@ -44,12 +44,12 @@
  </directive>
  <directive id="CSS.AllowedProperties">
   <file name="HTMLPurifier/CSSDefinition.php">
-   <line>447</line>
+   <line>460</line>
   </file>
  </directive>
  <directive id="CSS.ForbiddenProperties">
   <file name="HTMLPurifier/CSSDefinition.php">
-   <line>463</line>
+   <line>476</line>
   </file>
  </directive>
  <directive id="Cache.DefinitionImpl">
diff --git a/library/HTMLPurifier/CSSDefinition.php b/library/HTMLPurifier/CSSDefinition.php
index 07cc9417..a99172d4 100644
--- a/library/HTMLPurifier/CSSDefinition.php
+++ b/library/HTMLPurifier/CSSDefinition.php
@@ -370,6 +370,19 @@ class HTMLPurifier_CSSDefinition extends HTMLPurifier_Definition
         );
         $this->info['page-break-inside'] = new HTMLPurifier_AttrDef_Enum(array('auto', 'avoid'));
 
+        $border_radius = new HTMLPurifier_AttrDef_CSS_Composite(
+            array(
+                new HTMLPurifier_AttrDef_CSS_Percentage(true), // disallow negative
+                new HTMLPurifier_AttrDef_CSS_Length('0') // disallow negative
+            ));
+
+        $this->info['border-top-left-radius'] =
+        $this->info['border-top-right-radius'] =
+        $this->info['border-bottom-right-radius'] =
+        $this->info['border-bottom-left-radius'] = new HTMLPurifier_AttrDef_CSS_Multiple($border_radius, 2);
+        // TODO: support SLASH syntax
+        $this->info['border-radius'] = new HTMLPurifier_AttrDef_CSS_Multiple($border_radius, 4);
+
     }
 
     /**
diff --git a/tests/HTMLPurifier/AttrDef/CSSTest.php b/tests/HTMLPurifier/AttrDef/CSSTest.php
index 46779154..da2ab6b0 100644
--- a/tests/HTMLPurifier/AttrDef/CSSTest.php
+++ b/tests/HTMLPurifier/AttrDef/CSSTest.php
@@ -133,6 +133,8 @@ class HTMLPurifier_AttrDef_CSSTest extends HTMLPurifier_AttrDefHarness
         $this->assertDef('-khtml-opacity:.2;');
         $this->assertDef('filter:alpha(opacity=20);');
 
+        $this->assertDef('border-top-left-radius:55pt 25pt;');
+
     }
 
     public function testImportant()