diff --git a/ChangeLog b/ChangeLog
index 4ee7376f36..d56f296aa6 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Sun Jan 11 09:47:30 2009  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* hash.c (rb_hash_s_create): set nil as the value if assoc length
+	  is not enough.  [ruby-core:21249]
+
 Sat Jan 10 21:17:28 2009  Tanaka Akira  <akr@fsij.org>
 
 	* ext/socket/mkconstants.rb: don't generate unintended newlines.
diff --git a/hash.c b/hash.c
index b01c4184be..7203d8c4e9 100644
--- a/hash.c
+++ b/hash.c
@@ -348,10 +348,16 @@ rb_hash_s_create(int argc, VALUE *argv, VALUE klass)
 	    hash = hash_alloc(klass);
 	    for (i = 0; i < RARRAY_LEN(tmp); ++i) {
 		VALUE v = rb_check_array_type(RARRAY_PTR(tmp)[i]);
-		
+		VALUE key, val = Qnil;
+
 		if (NIL_P(v)) continue;
-		if (RARRAY_LEN(v) < 1 || 2 < RARRAY_LEN(v)) continue;
-		rb_hash_aset(hash, RARRAY_PTR(v)[0], RARRAY_PTR(v)[1]);
+		switch (RARRAY_LEN(v)) {
+		  case 2:
+		    val = RARRAY_PTR(v)[1];
+		  case 1:
+		    key = RARRAY_PTR(v)[0];
+		    rb_hash_aset(hash, key, val);
+		}
 	    }
 	    return hash;
 	}