diff --git a/OpenSSL/crypto/x509.c b/OpenSSL/crypto/x509.c
index a12220b..d62b504 100644
--- a/OpenSSL/crypto/x509.c
+++ b/OpenSSL/crypto/x509.c
@@ -519,6 +519,29 @@
     return Py_None;
 }
 
+static char crypto_X509_get_signature_algorithm_doc[] = "\n\
+Retrieve the signature algorithm used in the certificate\n\
+\n\
+Arguments: self - The X509 object\n\
+           args - The Python argument tuple, should be empty\n\
+Returns:   None\n\
+";
+
+static PyObject *
+crypto_X509_get_signature_algorithm(crypto_X509Obj *self, PyObject *args)
+{
+    ASN1_OBJECT *alg;
+    int nid;
+
+    if (!PyArg_ParseTuple(args, ":get_signature_algorithm"))
+        return NULL;
+
+    alg = self->x509->cert_info->signature->algorithm;
+    nid = OBJ_obj2nid(alg);
+    return PyString_FromString(OBJ_nid2ln(nid));
+}
+
+
 static char crypto_X509_sign_doc[] = "\n\
 Sign the certificate using the supplied key and digest\n\
 \n\
@@ -757,6 +780,7 @@
     ADD_METHOD(set_notAfter),
     ADD_METHOD(gmtime_adj_notBefore),
     ADD_METHOD(gmtime_adj_notAfter),
+    ADD_METHOD(get_signature_algorithm),
     ADD_METHOD(sign),
     ADD_METHOD(has_expired),
     ADD_METHOD(subject_name_hash),
diff --git a/OpenSSL/test/test_crypto.py b/OpenSSL/test/test_crypto.py
index 496dc59..fcf834f 100644
--- a/OpenSSL/test/test_crypto.py
+++ b/OpenSSL/test/test_crypto.py
@@ -652,6 +652,15 @@
         name = self._x509name()
         self.assertRaises(AttributeError, setattr, name, "no such thing", None)
 
+    def test_get_signature_algorithm(self):
+        """
+        L{X509Type.get_signature_algorithm} returns a string which means
+        the algorithm used to sign the certificate.
+        """
+        cert = load_certificate(FILETYPE_PEM, self.pemData)
+        self.assertEqual(cert.get_signature_algorithm(), "sha1WithRSAEncryption")
+        
+
 
     def test_attributes(self):
         """
diff --git a/doc/pyOpenSSL.tex b/doc/pyOpenSSL.tex
index 239133f..575eb8e 100644
--- a/doc/pyOpenSSL.tex
+++ b/doc/pyOpenSSL.tex
@@ -321,6 +321,10 @@
 Return the certificate serial number.
 \end{methoddesc}
 
+\begin{methoddesc}[X509]{get_signature_algorithm}{}
+Return the signature algorithem used in the certificate.
+\end{methoddesc}
+
 \begin{methoddesc}[X509]{get_subject}{}
 Return an X509Name object representing the subject of the certificate.
 \end{methoddesc}