diff --git a/ChangeLog b/ChangeLog
index 3f945746e8..bf87be6377 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Sep 10 12:25:24 2014  Eric Wong  <e@80x24.org>
+
+	* time.c (time_timespec): fix tv_nsec overflow
+	  [Bug #10144]
+
 Wed Sep 10 12:21:51 2014  Eric Wong  <e@80x24.org>
 
 	* ext/zlib/zlib.c (gzfile_reset): preserve ZSTREAM_FLAG_GZFILE
diff --git a/time.c b/time.c
index dfcbfbac0f..e5d55a87e0 100644
--- a/time.c
+++ b/time.c
@@ -2435,6 +2435,10 @@ time_timespec(VALUE num, int interval)
 	    d = modf(RFLOAT_VALUE(num), &f);
 	    if (d >= 0) {
 		t.tv_nsec = (int)(d*1e9+0.5);
+		if (t.tv_nsec >= 1000000000) {
+		    t.tv_nsec -= 1000000000;
+		    f += 1;
+		}
 	    }
 	    else if ((t.tv_nsec = (int)(-d*1e9+0.5)) > 0) {
 		t.tv_nsec = 1000000000 - t.tv_nsec;
diff --git a/version.h b/version.h
index 5849ac2085..e66485019b 100644
--- a/version.h
+++ b/version.h
@@ -1,6 +1,6 @@
 #define RUBY_VERSION "2.0.0"
 #define RUBY_RELEASE_DATE "2014-09-10"
-#define RUBY_PATCHLEVEL 562
+#define RUBY_PATCHLEVEL 563
 
 #define RUBY_RELEASE_YEAR 2014
 #define RUBY_RELEASE_MONTH 9