diff --git a/bob/utils.py b/bob/utils.py
index ea78c49..7ce4764 100644
--- a/bob/utils.py
+++ b/bob/utils.py
@@ -45,8 +45,46 @@ def pipe(a, b, indent=True):
 
 def archive_tree(dir, archive):
     """Creates a tar.gz archive from a given directory."""
+
+    abspath = os.path.abspath(dir)
+    base_root = None
+    transposed_base = None
+    is_top_level = False
+
     with tarfile.open(archive, 'w:gz') as tar:
-        tar.add(dir, arcname=os.path.basename(dir))
+
+        for root, _, files in os.walk(abspath):
+
+            # Mark the first pass as the top-level directory.
+            if is_top_level is None:
+                is_top_level = True
+
+            if not base_root:
+                base_root = root
+
+            # No path at all for the top-level directory.
+            if not is_top_level:
+                transposed_base = root[len(base_root)+1:]
+            else:
+                transposed_base = ''
+
+
+            for file in files:
+
+                standard_path = os.path.join(root, file)
+
+                if not transposed_base:
+                    transposed_path = file
+                else:
+                    transposed_path = os.path.join(transposed_base, file)
+
+                # Add the file to the archive, with the proper transposed path.
+                tar.add(standard_path, arcname=transposed_path)
+
+
+            # Close out the top-level directory marker.
+            is_top_level = False
+
 
 def extract_tree(archive, dir):
     """Extract tar.gz archive to a given directory."""