diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index f11e4257c..3e0c0ec0d 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -254,6 +254,7 @@ Wolf Siberski
 Wolfgang Baer
 Wolfgang Frech
 Wolfgang Werner
+Xavier Witdouck
 Yohann Roussel
 Yuji Yamano
 Yves Martin
diff --git a/WHATSNEW b/WHATSNEW
index 3fd4c4eef..824079115 100644
--- a/WHATSNEW
+++ b/WHATSNEW
@@ -9,6 +9,9 @@ Changes that could break older environments:
 * unrestrict the dbvendor names in the websphere element of the ejbjar task.
   Bugzilla Report 40475.
 
+* <env> nested element in <java>, <exec> and others is now case-insensitive
+  for windows OS. Bugzilla Report 28826.
+
 Fixed bugs:
 -----------
 
diff --git a/contributors.xml b/contributors.xml
index 14455ab18..c5b95829d 100644
--- a/contributors.xml
+++ b/contributors.xml
@@ -1010,6 +1010,10 @@
     <first>Wolfgang</first>
     <last>Werner</last>
   </name>
+  <name>
+    <first>Xavier</first>
+    <last>Witdouck</last>
+  </name>
   <name>
     <first>Yohann</first>
     <last>Roussel</last>
diff --git a/src/main/org/apache/tools/ant/taskdefs/Execute.java b/src/main/org/apache/tools/ant/taskdefs/Execute.java
index 11e049a84..1fb79bd3c 100644
--- a/src/main/org/apache/tools/ant/taskdefs/Execute.java
+++ b/src/main/org/apache/tools/ant/taskdefs/Execute.java
@@ -79,6 +79,9 @@ public class Execute {
     /** Used to destroy processes when the VM exits. */
     private static ProcessDestroyer processDestroyer = new ProcessDestroyer();
 
+    /** Used for replacing env variables */
+    private static boolean environmentCaseInSensitive = false;
+
     /*
      * Builds a command launcher for the OS and JVM we are running under.
      */
@@ -98,7 +101,7 @@ public class Execute {
             // OS/2
             shellLauncher = new OS2CommandLauncher(new CommandLauncher());
         } else if (Os.isFamily("windows")) {
-
+            environmentCaseInSensitive = true;
             CommandLauncher baseLauncher = new CommandLauncher();
 
             if (!Os.isFamily("win9x")) {
@@ -624,9 +627,17 @@ public class Execute {
         for (int i = 0; i < env.length; i++) {
             // Get key including "="
             String key = env[i].substring(0, env[i].indexOf('=') + 1);
+            if (environmentCaseInSensitive) {
+                // Nb: using default locale as key is a env name
+                key = key.toLowerCase();
+            }
             int size = osEnv.size();
             for (int j = 0; j < size; j++) {
-                if (((String) osEnv.elementAt(j)).startsWith(key)) {
+                String osEnvItem = (String) osEnv.elementAt(j);
+                if (environmentCaseInSensitive) {
+                    osEnvItem = osEnvItem.toLowerCase();
+                }
+                if (osEnvItem.startsWith(key)) {
                     osEnv.removeElementAt(j);
                     break;
                 }