diff --git a/dkim/__init__.py b/dkim/__init__.py
index 41829bb..6130bb7 100644
--- a/dkim/__init__.py
+++ b/dkim/__init__.py
@@ -265,7 +265,7 @@ def sign(message, selector, domain, privkey, identity=None,
 
     try:
         pk = parse_pem_private_key(privkey)
-    except UnparsableKeyError, e:
+    except UnparsableKeyError as e:
         raise KeyFormatError(str(e))
 
     if identity is not None and not identity.endswith(domain):
@@ -351,7 +351,7 @@ def verify(message, logger=None, dnsfunc=dnstxt):
 
     try:
         validate_signature_fields(sig)
-    except ValidationError, e:
+    except ValidationError as e:
         logger.error("signature fields failed to validate: %s" % e)
         return False
 
@@ -414,7 +414,7 @@ def verify(message, logger=None, dnsfunc=dnstxt):
         return False
     try:
         pk = parse_public_key(base64.b64decode(pub['p']))
-    except UnparsableKeyError, e:
+    except UnparsableKeyError as e:
         logger.error("could not parse public key: %s" % e)
         return False
 
diff --git a/dkim/crypto.py b/dkim/crypto.py
index 0288e0a..53d0f33 100644
--- a/dkim/crypto.py
+++ b/dkim/crypto.py
@@ -105,7 +105,7 @@ def parse_public_key(data):
         # Not sure why the [1:] is necessary to skip a byte.
         x = asn1_parse(ASN1_Object, data)
         pkd = asn1_parse(ASN1_RSAPublicKey, x[0][1][1:])
-    except ASN1FormatError, e:
+    except ASN1FormatError as e:
         raise UnparsableKeyError(str(e))
     pk = {
         'modulus': pkd[0][0],
@@ -122,7 +122,7 @@ def parse_private_key(data):
     """
     try:
         pka = asn1_parse(ASN1_RSAPrivateKey, data)
-    except ASN1FormatError, e:
+    except ASN1FormatError as e:
         raise UnparsableKeyError(str(e))
     pk = {
         'version': pka[0][0],
@@ -149,7 +149,7 @@ def parse_pem_private_key(data):
         raise UnparsableKeyError("Private key not found")
     try:
         pkdata = base64.b64decode(m.group(1))
-    except TypeError, e:
+    except TypeError as e:
         raise UnparsableKeyError(str(e))
     return parse_private_key(pkdata)