Index: src/main/java/org/jboss/resteasy/core/MethodInjectorImpl.java
===================================================================
--- src/main/java/org/jboss/resteasy/core/MethodInjectorImpl.java	(revision 892)
+++ src/main/java/org/jboss/resteasy/core/MethodInjectorImpl.java	(working copy)
@@ -15,6 +15,7 @@
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
 import java.lang.reflect.Type;
+import java.lang.reflect.TypeVariable;
 
 /**
  * @author <a href="mailto:bill@burkecentral.com">Bill Burke</a>
@@ -54,8 +55,22 @@
       Type[] genericParameterTypes = Types.getGenericParameterTypesOfGenericInterfaceMethod(root, method);
       for (int i = 0; i < method.getParameterTypes().length; i++)
       {
-         Class type = method.getParameterTypes()[i];
-         Type genericType = genericParameterTypes[i];
+         Class<?> type;
+         Type genericType;
+         
+         // the parameter type might be a type variable defined in a superclass
+         if (genericParameterTypes[i] instanceof TypeVariable<?>)
+         {
+            // try to find out the value of the type variable
+            genericType = Types.getActualValueOfTypeVariable(root, (TypeVariable<?>)genericParameterTypes[i]);
+            type = Types.getRawType(genericType);
+         } 
+         else
+         {
+            type = method.getParameterTypes()[i];
+            genericType = genericParameterTypes[i];
+         }
+         
          Annotation[] annotations = method.getParameterAnnotations()[i];
          params[i] = InjectorFactoryImpl.getParameterExtractor(root, method, type, genericType, annotations, factory);
       }
Index: src/main/java/org/jboss/resteasy/util/Types.java
===================================================================
--- src/main/java/org/jboss/resteasy/util/Types.java	(revision 892)
+++ src/main/java/org/jboss/resteasy/util/Types.java	(working copy)
@@ -264,4 +264,42 @@
       }
       return null;
    }
+   
+   /**
+    * Finds an actual value of a type variable. The method looks in a class hierarchy for a class defining the variable 
+    * and returns the value if present.
+    * @param clazz
+    * @param typeVariable
+    * @return actual type of the type variable
+    */
+   public static Type getActualValueOfTypeVariable(Class<?> clazz, TypeVariable<?> typeVariable)
+   {
+      if (typeVariable.getGenericDeclaration() instanceof Class<?>)
+      {
+         Class<?> classDeclaringTypeVariable = (Class<?>) typeVariable.getGenericDeclaration();
+         
+         // find the generic version of classDeclaringTypeVariable
+         while (clazz.getSuperclass() != null)
+         {
+            if (clazz.getSuperclass().equals(classDeclaringTypeVariable))
+            {
+               // found it
+               ParameterizedType parameterizedSuperclass = (ParameterizedType) clazz.getGenericSuperclass();
+               
+               for (int i = 0; i < classDeclaringTypeVariable.getTypeParameters().length; i++)
+               {
+                  TypeVariable<?> tv = classDeclaringTypeVariable.getTypeParameters()[i];
+                  if (tv.equals(typeVariable))
+                  {
+                     return parameterizedSuperclass.getActualTypeArguments()[i];
+                  }
+               }
+            }
+
+            clazz = clazz.getSuperclass();
+         }
+      }
+      
+      throw new RuntimeException("Unable to determine value of type parameter " + typeVariable);
+   }
 }