diff --git a/blacken.el b/blacken.el
index b5fabfd..83a9092 100644
--- a/blacken.el
+++ b/blacken.el
@@ -143,6 +143,30 @@ Show black output, if black exit abnormally and DISPLAY is t."
              (when display
                (pop-to-buffer errbuf))))))
 
+;;;###autoload
+(defun blacken-region (beg end)
+  "Try to blacken the current region (between BEG and END)."
+  (interactive (if (use-region-p)
+                   (list (region-beginning) (region-end))
+                 (list nil nil)))
+  (let* ((content (buffer-substring-no-properties beg end))
+         (indentation (with-temp-buffer
+                         (insert content)
+                         (goto-char (point-min))
+                         (back-to-indentation)
+                         (- (point) 1)))
+         (blackened (with-temp-buffer
+                      (insert content)
+                      (dotimes (i indentation)
+                        (indent-rigidly-left (point-min) (point-max)))
+                      (blacken-buffer)
+                      (dotimes (i indentation)
+                        (indent-rigidly-right (point-min) (point-max)))
+                      (buffer-string))))
+    (with-current-buffer (current-buffer)
+      (delete-region beg end)
+      (insert blackened))))
+
 ;;;###autoload
 (define-minor-mode blacken-mode
   "Automatically run black before saving."