diff --git a/contrib/gdb.py b/contrib/gdb.py
new file mode 100644
index 00000000..14574bb2
--- /dev/null
+++ b/contrib/gdb.py
@@ -0,0 +1,37 @@
+import gdb
+import re
+import gdb.printing
+
+class PuTTYBignumPrettyPrinter(gdb.printing.PrettyPrinter):
+    "Pretty-print PuTTY's Bignum type."
+    name = "Bignum"
+
+    def __init__(self, val):
+        super(PuTTYBignumPrettyPrinter, self).__init__(self.name)
+        self.val = val
+
+    def to_string(self):
+        type_BignumInt = gdb.lookup_type("BignumInt")
+        type_BignumIntPtr = type_BignumInt.pointer()
+        BIGNUM_INT_BITS = 8 * type_BignumInt.sizeof
+        array = self.val.cast(type_BignumIntPtr)
+        aget = lambda i: int(array[i]) & ((1 << BIGNUM_INT_BITS)-1)
+
+        try:
+            length = aget(0)
+            value = 0
+            for i in range(length):
+                value |= aget(i+1) << (BIGNUM_INT_BITS * i)
+            return "Bignum({:#x})".format(value)
+
+        except gdb.MemoryError:
+            address = int(array)
+            if address == 0:
+                return "Bignum(NULL)".format(address)
+            return "Bignum(invalid @ {:#x})".format(address)
+
+rcpp = gdb.printing.RegexpCollectionPrettyPrinter("PuTTY")
+rcpp.add_printer(PuTTYBignumPrettyPrinter.name, "^Bignum$",
+                 PuTTYBignumPrettyPrinter)
+
+gdb.printing.register_pretty_printer(None, rcpp)