diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/IndexModificationTimesTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/IndexModificationTimesTest.java
new file mode 100644
index 000000000..51c663499
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/IndexModificationTimesTest.java
@@ -0,0 +1,90 @@
+package org.eclipse.jgit.lib;
+
+import static org.junit.Assert.assertTrue;
+
+import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.dircache.DirCache;
+import org.eclipse.jgit.dircache.DirCacheEntry;
+import org.junit.Test;
+
+public class IndexModificationTimesTest extends RepositoryTestCase {
+
+	@Test
+	public void testLastModifiedTimes() throws Exception {
+		Git git = new Git(db);
+		String path = "file";
+		writeTrashFile(path, "content");
+		String path2 = "file2";
+		writeTrashFile(path2, "content2");
+
+		git.add().addFilepattern(path).call();
+		git.add().addFilepattern(path2).call();
+		git.commit().setMessage("commit").call();
+
+		DirCache dc = db.readDirCache();
+		DirCacheEntry entry = dc.getEntry(path);
+		DirCacheEntry entry2 = dc.getEntry(path);
+
+		assertTrue("last modified shall not be zero!",
+				entry.getLastModified() != 0);
+
+		assertTrue("last modified shall not be zero!",
+				entry2.getLastModified() != 0);
+
+		writeTrashFile(path, "new content");
+		git.add().addFilepattern(path).call();
+		git.commit().setMessage("commit2").call();
+
+		dc = db.readDirCache();
+		entry = dc.getEntry(path);
+		entry2 = dc.getEntry(path);
+
+		assertTrue("last modified shall not be zero!",
+				entry.getLastModified() != 0);
+
+		assertTrue("last modified shall not be zero!",
+				entry2.getLastModified() != 0);
+	}
+
+	@Test
+	public void testModify() throws Exception {
+		Git git = new Git(db);
+		String path = "file";
+		writeTrashFile(path, "content");
+
+		git.add().addFilepattern(path).call();
+		git.commit().setMessage("commit").call();
+
+		DirCache dc = db.readDirCache();
+		DirCacheEntry entry = dc.getEntry(path);
+
+		long masterLastMod = entry.getLastModified();
+
+		git.checkout().setCreateBranch(true).setName("side").call();
+
+		Thread.sleep(10);
+		String path2 = "file2";
+		writeTrashFile(path2, "side content");
+		git.add().addFilepattern(path2).call();
+		git.commit().setMessage("commit").call();
+
+		dc = db.readDirCache();
+		entry = dc.getEntry(path);
+
+		long sideLastMode = entry.getLastModified();
+
+		Thread.sleep(2000);
+
+		writeTrashFile(path, "uncommitted content");
+		git.checkout().setName("master").call();
+
+		dc = db.readDirCache();
+		entry = dc.getEntry(path);
+
+		assertTrue("shall have equal mod time!", masterLastMod == sideLastMode);
+		assertTrue("shall not equal master timestamp!",
+				entry.getLastModified() == masterLastMod);
+
+	}
+
+}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java b/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java
index 22a855832..8b15a27a0 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/dircache/DirCacheCheckout.java
@@ -332,8 +332,14 @@ public class DirCacheCheckout {
 					// conflict
 					update(m.getEntryPathString(), m.getEntryObjectId(),
 							m.getEntryFileMode());
-				else
-					keep(i.getDirCacheEntry());
+				else {
+					// update the timestamp of the index with the one from the
+					// file if not set, as we are sure to be in sync here.
+					DirCacheEntry entry = i.getDirCacheEntry();
+					if (entry.getLastModified() == 0)
+						entry.setLastModified(f.getEntryLastModified());
+					keep(entry);
+				}
 			} else
 				// The index contains a folder
 				keep(i.getDirCacheEntry());