Index: src/jvm/clojure/lang/Numbers.java
===================================================================
--- src/jvm/clojure/lang/Numbers.java	(revision 1159)
+++ src/jvm/clojure/lang/Numbers.java	(working copy)
@@ -450,7 +450,10 @@
 
 	//public Number subtract(Number x, Number y);
 	final public Number negate(Number x){
-		return -x.intValue();
+		int val = x.intValue();
+		if(val > Integer.MIN_VALUE)
+			return -val;
+		return BigInteger.valueOf(-(long) val);
 	}
 
 	public Number inc(Number x){