diff --git a/cas-client-core/src/main/java/org/jasig/cas/client/util/CommonUtils.java b/cas-client-core/src/main/java/org/jasig/cas/client/util/CommonUtils.java
index b8e4a62..1904de8 100644
--- a/cas-client-core/src/main/java/org/jasig/cas/client/util/CommonUtils.java
+++ b/cas-client-core/src/main/java/org/jasig/cas/client/util/CommonUtils.java
@@ -138,7 +138,7 @@ public final class CommonUtils {
      */
     public static final String constructRedirectUrl(final String casServerLoginUrl, final String serviceParameterName, final String serviceUrl, final boolean renew, final boolean gateway) {
         try {
-        return casServerLoginUrl + "?" + serviceParameterName + "="
+        return casServerLoginUrl + (casServerLoginUrl.indexOf("?") != -1 ? "&" : "?") + serviceParameterName + "="
                     + URLEncoder.encode(serviceUrl, "UTF-8")
                     + (renew ? "&renew=true" : "")
                     + (gateway ? "&gateway=true" : "");
diff --git a/cas-client-core/src/test/java/org/jasig/cas/client/util/CommonUtilsTests.java b/cas-client-core/src/test/java/org/jasig/cas/client/util/CommonUtilsTests.java
index a75abc2..99cb6e2 100644
--- a/cas-client-core/src/test/java/org/jasig/cas/client/util/CommonUtilsTests.java
+++ b/cas-client-core/src/test/java/org/jasig/cas/client/util/CommonUtilsTests.java
@@ -19,6 +19,22 @@ import java.util.Collection;
  */
 public final class CommonUtilsTests extends TestCase {
 
+    public void testRedirectUrlWithParam() {
+        final String loginUrl = "http://localhost:8080/login?myName=foo";
+        final String fullyConstructedUrl = CommonUtils.constructRedirectUrl(loginUrl, "foo", "foo", false, false);
+
+        int count = 0;
+        final char[] chars = fullyConstructedUrl.toCharArray();
+
+        for (int i = 0; i < chars.length; i++) {
+            if (chars[i] == '?') {
+                count ++;
+            }
+        }
+
+        assertEquals(1, count);
+    }
+
     public void testAssertNotNull() {
         final String CONST_MESSAGE = "test";
         CommonUtils.assertNotNull(new Object(), CONST_MESSAGE);