diff --git a/ChangeLog b/ChangeLog
index 26978deae3..5011128641 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Apr 19 23:14:45 2010  Yusuke Endoh  <mame@tsg.ne.jp>
+
+	* thread.c (rb_thread_blocking_region, rb_thread_blocking_region_end):
+	  preserve errno.  [Bug #2606] [ruby-core:28924]
+
 Mon Apr 19 19:41:10 2010  URABE Shyouhei  <shyouhei@ruby-lang.org>
 
 	* lib/fileutils.rb (FileUtils::cp_r): backport r11156 from ruby_1_8.
diff --git a/thread.c b/thread.c
index 40a3483b75..094427f06c 100644
--- a/thread.c
+++ b/thread.c
@@ -1054,10 +1054,12 @@ rb_thread_blocking_region_begin(void)
 void
 rb_thread_blocking_region_end(struct rb_blocking_region_buffer *region)
 {
+    int saved_errno = errno;
     rb_thread_t *th = GET_THREAD();
     blocking_region_end(th, region);
     xfree(region);
     RUBY_VM_CHECK_INTS();
+    errno = saved_errno;
 }
 
 /*
@@ -1103,6 +1105,7 @@ rb_thread_blocking_region(
 {
     VALUE val;
     rb_thread_t *th = GET_THREAD();
+    int saved_errno = 0;
 
     if (ubf == RUBY_UBF_IO || ubf == RUBY_UBF_PROCESS) {
 	ubf = ubf_select;
@@ -1111,7 +1114,9 @@ rb_thread_blocking_region(
 
     BLOCKING_REGION({
 	val = func(data1);
+	saved_errno = errno;
     }, ubf, data2);
+    errno = saved_errno;
 
     return val;
 }