diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/BaseRepositoryBuilder.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/BaseRepositoryBuilder.java
index 4fa74630f..f1e54ed1d 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/BaseRepositoryBuilder.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/BaseRepositoryBuilder.java
@@ -50,7 +50,7 @@
 import static org.eclipse.jgit.lib.Constants.GIT_ALTERNATE_OBJECT_DIRECTORIES_KEY;
 import static org.eclipse.jgit.lib.Constants.GIT_CEILING_DIRECTORIES_KEY;
 import static org.eclipse.jgit.lib.Constants.GIT_DIR_KEY;
-import static org.eclipse.jgit.lib.Constants.GIT_INDEX_KEY;
+import static org.eclipse.jgit.lib.Constants.GIT_INDEX_FILE_KEY;
 import static org.eclipse.jgit.lib.Constants.GIT_OBJECT_DIRECTORY_KEY;
 import static org.eclipse.jgit.lib.Constants.GIT_WORK_TREE_KEY;
 
@@ -339,7 +339,7 @@ public B readEnvironment(SystemReader sr) {
 		}
 
 		if (getIndexFile() == null) {
-			String val = sr.getenv(GIT_INDEX_KEY);
+			String val = sr.getenv(GIT_INDEX_FILE_KEY);
 			if (val != null)
 				setIndexFile(new File(val));
 		}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Constants.java b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Constants.java
index afeaffcc9..139093a08 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/lib/Constants.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/lib/Constants.java
@@ -288,7 +288,7 @@ public final class Constants {
 	/**
 	 * The environment variable that tells us which file holds the Git index.
 	 */
-	public static final String GIT_INDEX_KEY = "GIT_INDEX";
+	public static final String GIT_INDEX_FILE_KEY = "GIT_INDEX_FILE";
 
 	/**
 	 * The environment variable that tells us where objects are stored