diff --git a/src/etc/testcases/taskdefs/zip.xml b/src/etc/testcases/taskdefs/zip.xml
index 0163bc564..afac90e2a 100644
--- a/src/etc/testcases/taskdefs/zip.xml
+++ b/src/etc/testcases/taskdefs/zip.xml
@@ -95,6 +95,13 @@
          update="true" />
   </target>
 
+  <!-- Bugzilla Report 18403 -->
+  <target name="testPrefixAddsDir">
+    <zip destfile="test3.zip" filesonly="false">
+      <zipfileset dir="." prefix="test" includes="zip.xml"/>
+    </zip>
+  </target>
+
   <target name="cleanup">
     <delete file="test3.zip"/>
     <delete file="test4.zip"/>
diff --git a/src/testcases/org/apache/tools/ant/taskdefs/ZipTest.java b/src/testcases/org/apache/tools/ant/taskdefs/ZipTest.java
index c98e084fb..3d85301ff 100644
--- a/src/testcases/org/apache/tools/ant/taskdefs/ZipTest.java
+++ b/src/testcases/org/apache/tools/ant/taskdefs/ZipTest.java
@@ -57,6 +57,7 @@ import org.apache.tools.ant.BuildFileTest;
 
 import java.io.File;
 import java.io.IOException;
+import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
 import java.util.Enumeration;
 
@@ -134,4 +135,13 @@ public class ZipTest extends BuildFileTest {
     public void testUpdateIsNecessary() {
         expectLogContaining("testUpdateIsNecessary", "Updating");
     }
+
+    // Bugzilla Report 18403
+    public void testPrefixAddsDir() throws IOException {
+        executeTarget("testPrefixAddsDir");
+        File archive = getProject().resolveFile("test3.zip");
+        ZipFile zf = new ZipFile(archive);
+        ZipEntry ze = zf.getEntry("test/");
+        assertNotNull("test/ has been added", ze);
+    }
 }