diff --git a/ChangeLog b/ChangeLog
index eac30e7087..ac29b59f26 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+Thu Nov 10 05:17:25 2011  Koichi Sasada  <ko1@atdot.net>
+
+	* cont.c (rb_fiber_m_transfer, rb_fiber_resume): prohibit using
+	  "resume" after "transfer" method are used.  You should not mix
+	  "resume" fiber and "transfer" fiber.
+	  [Bug #5526]
+
+	* NEWS: add information about this change.
+
 Wed Nov  9 11:40:37 2011  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* template/Doxyfile.tmpl (INCLUDE_PATH): add srcdir and include.
diff --git a/NEWS b/NEWS
index b52a7d14a2..b6ddc634f5 100644
--- a/NEWS
+++ b/NEWS
@@ -32,6 +32,10 @@ with all sufficient information, see the ChangeLog file.
       * Time#to_s returned encoding defaults to US-ASCII but automatically
         transcodes to Encoding.default_internal if it is set.
 
+  * Fiber
+    * incompatible changes:
+      * Fiber#resume cannot resume a fiber which invokes "Fiber#transfer".
+
 * net/imap
   * new methods:
     * Net::IMAP.default_port
diff --git a/cont.c b/cont.c
index 0ed1f2c032..cb934f79bc 100644
--- a/cont.c
+++ b/cont.c
@@ -103,6 +103,12 @@ typedef struct rb_fiber_struct {
     enum fiber_status status;
     struct rb_fiber_struct *prev_fiber;
     struct rb_fiber_struct *next_fiber;
+    /* If a fiber invokes "transfer",
+     * then this fiber can't "resume" any more after that.
+     * You shouldn't mix "transfer" and "resume".
+     */
+    int transfered;
+
 #if FIBER_USE_NATIVE
 #ifdef _WIN32
     void *fib_handle;
@@ -1322,6 +1328,9 @@ rb_fiber_resume(VALUE fibval, int argc, VALUE *argv)
     if (fib->prev != Qnil || fib->cont.type == ROOT_FIBER_CONTEXT) {
 	rb_raise(rb_eFiberError, "double resume");
     }
+    if (fib->transfered != 0) {
+	rb_raise(rb_eFiberError, "cannot resume transferred Fiber");
+    }
 
     return fiber_switch(fibval, argc, argv, 1);
 }
@@ -1389,9 +1398,12 @@ rb_fiber_m_resume(int argc, VALUE *argv, VALUE fib)
  *  back to this fiber before it can yield and resume.
  */
 static VALUE
-rb_fiber_m_transfer(int argc, VALUE *argv, VALUE fib)
+rb_fiber_m_transfer(int argc, VALUE *argv, VALUE fibval)
 {
-    return rb_fiber_transfer(fib, argc, argv);
+    rb_fiber_t *fib;
+    GetFiberPtr(fibval, fib);
+    fib->transfered = 1;
+    return rb_fiber_transfer(fibval, argc, argv);
 }
 
 /*