diff --git a/CHANGES b/CHANGES
index a4ae46550..139b20bbd 100644
--- a/CHANGES
+++ b/CHANGES
@@ -5,6 +5,9 @@
 
  Changes between 0.9.3a and 0.9.4
 
+  *) DES CBC did not update the IV. Weird.
+     [Ben Laurie]
+
   *) When bntest is run from "make test" it drives bc to check its
      calculations, as well as internally checking them. If an internal check
      fails, it needs to cause bc to give a non-zero result or make test carries
diff --git a/crypto/des/cbc_enc.c b/crypto/des/cbc_enc.c
index 4ccabc911..668fb150d 100644
--- a/crypto/des/cbc_enc.c
+++ b/crypto/des/cbc_enc.c
@@ -94,6 +94,9 @@ void des_cbc_encrypt(const unsigned char *in, unsigned char *out, long length,
 			tout0=tin[0]; l2c(tout0,out);
 			tout1=tin[1]; l2c(tout1,out);
 			}
+		iv = &(*ivec)[0];
+		l2c(tout0,iv);
+		l2c(tout1,iv);
 		}
 	else
 		{
@@ -122,6 +125,9 @@ void des_cbc_encrypt(const unsigned char *in, unsigned char *out, long length,
 		/*	xor0=tin0;
 			xor1=tin1; */
 			}
+		iv = &(*ivec)[0];
+		l2c(xor0,iv);
+		l2c(xor1,iv);
 		}
 	tin0=tin1=tout0=tout1=xor0=xor1=0;
 	tin[0]=tin[1]=0;