diff --git a/lib/util.js b/lib/util.js
index 48003a3..74dc99e 100644
--- a/lib/util.js
+++ b/lib/util.js
@@ -187,14 +187,14 @@ exports.propParse = function( data, options )
 
         if ( keywords['abstract'] )
         {
-            if ( value instanceof Array )
+            if ( !( value instanceof Array ) )
             {
-                value = exports.createAbstractMethod.apply( this, value );
-            }
-            else
-            {
-                value = exports.createAbstractMethod();
+                throw TypeError(
+                    "Missing parameter list for abstract method: " + name
+                );
             }
+
+            value = exports.createAbstractMethod.apply( this, value );
         }
 
         // if an 'each' callback was provided, pass the data before parsing it
diff --git a/test/test-class-abstract.js b/test/test-class-abstract.js
index 49e9b47..9f9e28f 100644
--- a/test/test-class-abstract.js
+++ b/test/test-class-abstract.js
@@ -197,3 +197,13 @@ assert.doesNotThrow(
         "no definition was provided"
 );
 
+
+assert.throws( function()
+{
+    Class.extend(
+    {
+        // not an array (invalid)
+        'abstract foo': 'scalar',
+    } );
+}, TypeError, "Abstract methods must be declared as arrays" );
+
diff --git a/test/test-util-prop-parse-keywords.js b/test/test-util-prop-parse-keywords.js
index 49ff95d..f98415c 100644
--- a/test/test-util-prop-parse-keywords.js
+++ b/test/test-util-prop-parse-keywords.js
@@ -27,7 +27,7 @@ var common = require( './common' ),
     util   = common.require( 'util' );
 
 var data = {
-    'abstract foo': null,
+    'abstract foo': [],
 }
 
 var abstract_methods = [],
@@ -56,7 +56,7 @@ assert.ok(
 //
 // custom parser
 var data2 = {
-        foo: 'bar',
+        foo: [],
     },
     map = {
         foo: { 'abstract': true },