diff --git a/src/main/org/apache/ant/antunit/antlib.xml b/src/main/org/apache/ant/antunit/antlib.xml
index 82d2fb5..9fe2ed3 100644
--- a/src/main/org/apache/ant/antunit/antlib.xml
+++ b/src/main/org/apache/ant/antunit/antlib.xml
@@ -104,7 +104,8 @@ under the License.
     <sequential>
       <au:assertPropertySet message="@{message}" name="@{name}"/>
       <au:assertTrue message="@{message}">
-        <contains string="@{name}" substring="@{value}"/>
+        <contains string="@{name}" substring="@{value}"
+                  casesensitive="@{casesensitive}"/>
       </au:assertTrue>
     </sequential>
   </macrodef>