diff -r 23cdb1f98069 -r ea8bf21980fa src/org/python/core/PyLong.java
--- a/src/org/python/core/PyLong.java	Mon Mar 18 21:06:33 2013 -0700
+++ b/src/org/python/core/PyLong.java	Mon Mar 18 22:24:15 2013 -0700
@@ -39,6 +39,8 @@
 
     private final BigInteger value;
 
+    private static final char[] LOOKUP = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
+
     public BigInteger getValue() {
         return value;
     }
@@ -994,12 +996,39 @@
 
     @ExposedMethod(doc = BuiltinDocs.long___hex___doc)
     final PyString long___hex__() {
-        String s = getValue().toString(16);
-        if (s.startsWith("-")) {
-            return new PyString("-0x" + s.substring(1, s.length()) + "L");
-        } else {
-            return new PyString("0x" + s + "L");
+        /*
+        Issue 2013:
+        getValue() returns a BigInteger object reference, and BigInteger.toString(radix) is known to
+        take computationally expensive time to compute for large numbers.
+         */
+        //String s = getValue().toString(16);
+
+        BigInteger value = getValue();
+
+        // obvious shortcut
+        if (value.signum() == 0)
+            return new PyString("0x0L");
+
+        // we want to work in absolute numeric value (negative sign is added afterward)
+        String s = toHexString(getValue().abs().toByteArray());
+        String prefix = value.signum() < 0 ? "-0x" : "0x";
+
+        return new PyString(prefix + s + "L");
+    }
+
+    final static String toHexString(byte[] input) {
+        if (input == null || input.length <= 0)
+            return null;
+
+        char[] output = new char[input.length * 2];
+
+        for (int i = 0; i < input.length; i++) {
+            output[2*i] = LOOKUP[(input[i] >> 4) & 0x0F];
+            output[2*i+1] = LOOKUP[input[i] & 0x0F];
         }
+
+        // before returning the char array as string, remove leading zeroes, but not the last one
+        return new String(output).replaceFirst("^0+(?!$)", "");
     }
 
     @ExposedMethod(doc = BuiltinDocs.long___str___doc)