diff --git a/lisp/ChangeLog b/lisp/ChangeLog
index 8f00403c39b..fe06ac671b7 100644
--- a/lisp/ChangeLog
+++ b/lisp/ChangeLog
@@ -1,3 +1,8 @@
+2014-11-15  Fabián Ezequiel Gallina  <fgallina@gnu.org>
+
+	* progmodes/python.el (python-indent-region): Use
+	python-indent-line and skip special cases.  (Bug#18843)
+
 2014-11-15  Michael Albinus  <michael.albinus@gmx.de>
 
 	* vc/vc-hg.el (vc-hg-state): Disable pager.  (Bug#18940)
diff --git a/lisp/progmodes/python.el b/lisp/progmodes/python.el
index 95fc52d4d54..5f8d7a29fa6 100644
--- a/lisp/progmodes/python.el
+++ b/lisp/progmodes/python.el
@@ -1061,24 +1061,34 @@ Called from a program, START and END specify the region to indent."
       (or (bolp) (forward-line 1))
       (while (< (point) end)
         (or (and (bolp) (eolp))
-            (let (word)
-              (forward-line -1)
-              (back-to-indentation)
-              (setq word (current-word))
-              (forward-line 1)
-              (when (and word
-                         ;; Don't mess with strings, unless it's the
-                         ;; enclosing set of quotes.
-                         (or (not (python-syntax-context 'string))
-                             (eq
-                              (syntax-after
-                               (+ (1- (point))
-                                  (current-indentation)
-                                  (python-syntax-count-quotes (char-after) (point))))
-                              (string-to-syntax "|"))))
-                (beginning-of-line)
-                (delete-horizontal-space)
-                (indent-to (python-indent-calculate-indentation)))))
+            (when (and
+                   ;; Skip if previous line is empty or a comment.
+                   (save-excursion
+                     (let ((line-is-comment-p
+                            (python-info-current-line-comment-p)))
+                       (forward-line -1)
+                       (not
+                        (or (and (python-info-current-line-comment-p)
+                                 ;; Unless this line is a comment too.
+                                 (not line-is-comment-p))
+                            (python-info-current-line-empty-p)))))
+                   ;; Don't mess with strings, unless it's the
+                   ;; enclosing set of quotes.
+                   (or (not (python-syntax-context 'string))
+                       (eq
+                        (syntax-after
+                         (+ (1- (point))
+                            (current-indentation)
+                            (python-syntax-count-quotes (char-after) (point))))
+                        (string-to-syntax "|")))
+                   ;; Skip if current line is a block start, a
+                   ;; dedenter or block ender.
+                   (save-excursion
+                     (back-to-indentation)
+                     (not (looking-at
+                           (python-rx
+                            (or block-start dedenter block-ender))))))
+              (python-indent-line)))
         (forward-line 1))
       (move-marker end nil))))
 
diff --git a/test/ChangeLog b/test/ChangeLog
index a5ee4b60589..971a4f8f400 100644
--- a/test/ChangeLog
+++ b/test/ChangeLog
@@ -1,3 +1,9 @@
+2014-11-15  Fabián Ezequiel Gallina  <fgallina@gnu.org>
+
+	* automated/python-tests.el (python-indent-region-1)
+	(python-indent-region-2, python-indent-region-3)
+	(python-indent-region-4, python-indent-region-5): New tests.
+
 2014-11-08  Michael Albinus  <michael.albinus@gmx.de>
 
 	Backport Tramp changes from trunk.
diff --git a/test/automated/python-tests.el b/test/automated/python-tests.el
index 39195fd7086..8c657c38b64 100644
--- a/test/automated/python-tests.el
+++ b/test/automated/python-tests.el
@@ -725,6 +725,110 @@ def b()
    (python-tests-self-insert ":")
    (should (= (current-indentation) 0))))
 
+(ert-deftest python-indent-region-1 ()
+  "Test indentation case from Bug#18843."
+  (let ((contents "
+def foo ():
+    try:
+        pass
+    except:
+        pass
+"))
+    (python-tests-with-temp-buffer
+     contents
+     (python-indent-region (point-min) (point-max))
+     (should (string= (buffer-substring-no-properties (point-min) (point-max))
+                      contents)))))
+
+(ert-deftest python-indent-region-2 ()
+  "Test region indentation on comments."
+  (let ((contents "
+def f():
+    if True:
+        pass
+
+# This is
+# some multiline
+# comment
+"))
+    (python-tests-with-temp-buffer
+     contents
+     (python-indent-region (point-min) (point-max))
+     (should (string= (buffer-substring-no-properties (point-min) (point-max))
+                      contents)))))
+
+(ert-deftest python-indent-region-3 ()
+  "Test region indentation on comments."
+  (let ((contents "
+def f():
+    if True:
+        pass
+# This is
+# some multiline
+# comment
+")
+        (expected "
+def f():
+    if True:
+        pass
+    # This is
+    # some multiline
+    # comment
+"))
+    (python-tests-with-temp-buffer
+     contents
+     (python-indent-region (point-min) (point-max))
+     (should (string= (buffer-substring-no-properties (point-min) (point-max))
+                      expected)))))
+
+(ert-deftest python-indent-region-4 ()
+  "Test region indentation block starts, dedenders and enders."
+  (let ((contents "
+def f():
+    if True:
+a  = 5
+    else:
+            a = 10
+    return a
+")
+        (expected "
+def f():
+    if True:
+        a  = 5
+    else:
+        a = 10
+    return a
+"))
+    (python-tests-with-temp-buffer
+     contents
+     (python-indent-region (point-min) (point-max))
+     (should (string= (buffer-substring-no-properties (point-min) (point-max))
+                      expected)))))
+
+(ert-deftest python-indent-region-5 ()
+  "Test region indentation leaves strings untouched (start delimiter)."
+  (let ((contents "
+def f():
+'''
+this is
+a multiline
+string
+'''
+")
+        (expected "
+def f():
+    '''
+this is
+a multiline
+string
+'''
+"))
+    (python-tests-with-temp-buffer
+     contents
+     (python-indent-region (point-min) (point-max))
+     (should (string= (buffer-substring-no-properties (point-min) (point-max))
+                      expected)))))
+
 
 ;;; Navigation