diff --git a/Lib/SimpleXMLRPCServer.py b/Lib/SimpleXMLRPCServer.py
index 5f6e9d0..f74ca54 100644
--- a/Lib/SimpleXMLRPCServer.py
+++ b/Lib/SimpleXMLRPCServer.py
@@ -464,7 +464,8 @@
 
             self.end_headers()
         else:
-            # got a valid XML RPC response
+            # Got a valid XML RPC response; convert to bytes first
+            response = response.encode("utf-8")
             self.send_response(200)
             self.send_header("Content-type", "text/xml")
             self.send_header("Content-length", str(len(response)))
diff --git a/Lib/smtplib.py b/Lib/smtplib.py
index e10e327..0b4cbf0 100755
--- a/Lib/smtplib.py
+++ b/Lib/smtplib.py
@@ -295,12 +295,14 @@
         if self.debuglevel > 0: print("connect:", msg, file=stderr)
         return (code, msg)
 
-    def send(self, str):
-        """Send `str' to the server."""
-        if self.debuglevel > 0: print('send:', repr(str), file=stderr)
+    def send(self, s):
+        """Send `s' to the server."""
+        if self.debuglevel > 0: print('send:', repr(s), file=stderr)
         if self.sock:
+            if isinstance(s, str):
+                s = s.encode("ascii")
             try:
-                self.sock.sendall(str)
+                self.sock.sendall(s)
             except socket.error:
                 self.close()
                 raise SMTPServerDisconnected('Server not connected')
diff --git a/Lib/test/test_ftplib.py b/Lib/test/test_ftplib.py
index 62aae05..d782c53 100644
--- a/Lib/test/test_ftplib.py
+++ b/Lib/test/test_ftplib.py
@@ -18,7 +18,7 @@
     except socket.timeout:
         pass
     else:
-        conn.send("1 Hola mundo\n")
+        conn.send(b"1 Hola mundo\n")
         conn.close()
     finally:
         serv.close()
diff --git a/Lib/test/test_poplib.py b/Lib/test/test_poplib.py
index ef8565c..983cf21 100644
--- a/Lib/test/test_poplib.py
+++ b/Lib/test/test_poplib.py
@@ -19,7 +19,7 @@
     except socket.timeout:
         pass
     else:
-        conn.send("+ Hola mundo\n")
+        conn.send(b"+ Hola mundo\n")
         conn.close()
     finally:
         serv.close()
diff --git a/Lib/test/test_smtplib.py b/Lib/test/test_smtplib.py
index 00c3ad4..4151d6b 100644
--- a/Lib/test/test_smtplib.py
+++ b/Lib/test/test_smtplib.py
@@ -50,7 +50,7 @@
 
     def setUp(self):
         self.evt = threading.Event()
-        servargs = (self.evt, "220 Hola mundo\n")
+        servargs = (self.evt, b"220 Hola mundo\n")
         threading.Thread(target=server, args=servargs).start()
 
         # wait until server thread has assigned a port number
diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py
index c01d998..97445a0 100644
--- a/Lib/test/test_socket.py
+++ b/Lib/test/test_socket.py
@@ -498,7 +498,7 @@
         sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         sock.settimeout(1)
         sock.close()
-        self.assertRaises(socket.error, sock.send, "spam")
+        self.assertRaises(socket.error, sock.send, b"spam")
 
     def testNewAttributes(self):
         # testing .family, .type and .protocol
diff --git a/Lib/test/test_urllib2_localnet.py b/Lib/test/test_urllib2_localnet.py
index dde9504..f0b5dea 100644
--- a/Lib/test/test_urllib2_localnet.py
+++ b/Lib/test/test_urllib2_localnet.py
@@ -139,7 +139,7 @@
         # not.
         #request_handler.send_header('Connection', 'close')
         request_handler.end_headers()
-        request_handler.wfile.write("Proxy Authentication Required.")
+        request_handler.wfile.write(b"Proxy Authentication Required.")
         return False
 
     def handle_request(self, request_handler):
@@ -210,9 +210,10 @@
             self.send_response(200, "OK")
             self.send_header("Content-Type", "text/html")
             self.end_headers()
-            self.wfile.write("You've reached %s!<BR>" % self.path)
-            self.wfile.write("Our apologies, but our server is down due to "
-                              "a sudden zombie invasion.")
+            self.wfile.write(bytes("You've reached %s!<BR>" % self.path,
+                                   "ascii"))
+            self.wfile.write(b"Our apologies, but our server is down due to "
+                             b"a sudden zombie invasion.")
 
 # Test cases
 
diff --git a/Modules/socketmodule.c b/Modules/socketmodule.c
index 9f312ea..e4e30b8 100644
--- a/Modules/socketmodule.c
+++ b/Modules/socketmodule.c
@@ -947,7 +947,7 @@
 #ifdef linux
 		if (a->sun_path[0] == 0) {  /* Linux abstract namespace */
 			addrlen -= (sizeof(*a) - sizeof(a->sun_path));
-			return PyBytes_FromStringAndSize(a->sun_path, addrlen);
+			return PyString_FromStringAndSize(a->sun_path, addrlen);
 		}
 		else
 #endif /* linux */
@@ -1273,12 +1273,12 @@
 
 			addr = (struct sockaddr_sco *)addr_ret;
 			_BT_SCO_MEMB(addr, family) = AF_BLUETOOTH;
-			if (!PyBytes_Check(args)) {
+			if (!PyString_Check(args)) {
 				PyErr_SetString(socket_error, "getsockaddrarg: "
 						"wrong format");
 				return 0;
 			}
-			straddr = PyBytes_AS_STRING(args);
+			straddr = PyString_AS_STRING(args);
 			if (setbdaddr(straddr, &_BT_SCO_MEMB(addr, bdaddr)) < 0)
 				return 0;
 
@@ -1313,7 +1313,7 @@
 				Py_Type(args)->tp_name);
 			return 0;
 		}
-		if (!PyArg_ParseTuple(args, "si|iis#", &interfaceName,
+		if (!PyArg_ParseTuple(args, "si|iiy#", &interfaceName,
 				      &protoNumber, &pkttype, &hatype,
 				      &haddr, &halen))
 			return 0;
@@ -1606,7 +1606,7 @@
 	}
 	else {
 		PyErr_Clear();
-		if (!PyArg_ParseTuple(args, "iis#:setsockopt",
+		if (!PyArg_ParseTuple(args, "iiy#:setsockopt",
 				      &level, &optname, &buf, &buflen))
 			return NULL;
 	}
@@ -1662,19 +1662,16 @@
 				"getsockopt buflen out of range");
 		return NULL;
 	}
-	buf = PyBytes_FromStringAndSize((char *)NULL, buflen);
+	buf = PyString_FromStringAndSize((char *)NULL, buflen);
 	if (buf == NULL)
 		return NULL;
 	res = getsockopt(s->sock_fd, level, optname,
-			 (void *)PyBytes_AS_STRING(buf), &buflen);
+			 (void *)PyString_AS_STRING(buf), &buflen);
 	if (res < 0) {
 		Py_DECREF(buf);
 		return s->errorhandler();
 	}
-	if (PyBytes_Resize(buf, buflen) < 0) {
-		Py_DECREF(buf);
-		return NULL;
-	}
+	_PyString_Resize(&buf, buflen);
 	return buf;
 }
 
@@ -2097,12 +2094,12 @@
 	}
 
 	/* Allocate a new string. */
-	buf = PyBytes_FromStringAndSize((char *) 0, recvlen);
+	buf = PyString_FromStringAndSize((char *) 0, recvlen);
 	if (buf == NULL)
 		return NULL;
 
 	/* Call the guts */
-	outlen = sock_recv_guts(s, PyBytes_AS_STRING(buf), recvlen, flags);
+	outlen = sock_recv_guts(s, PyString_AS_STRING(buf), recvlen, flags);
 	if (outlen < 0) {
 		/* An error occurred, release the string and return an
 		   error. */
@@ -2112,9 +2109,7 @@
 	if (outlen != recvlen) {
 		/* We did not read as many bytes as we anticipated, resize the
 		   string if possible and be successful. */
-		if (PyBytes_Resize(buf, outlen) < 0)
-			/* Oopsy, not so successful after all. */
-			return NULL;
+		_PyString_Resize(&buf, outlen);
 	}
 
 	return buf;
@@ -2270,11 +2265,11 @@
 		return NULL;
 	}
 
-	buf = PyBytes_FromStringAndSize((char *) 0, recvlen);
+	buf = PyString_FromStringAndSize((char *) 0, recvlen);
 	if (buf == NULL)
 		return NULL;
 
-	outlen = sock_recvfrom_guts(s, PyBytes_AS_STRING(buf),
+	outlen = sock_recvfrom_guts(s, PyString_AS_STRING(buf),
 				    recvlen, flags, &addr);
 	if (outlen < 0) {
 		goto finally;
@@ -2283,7 +2278,7 @@
 	if (outlen != recvlen) {
 		/* We did not read as many bytes as we anticipated, resize the
 		   string if possible and be succesful. */
-		if (PyBytes_Resize(buf, outlen) < 0)
+		if (_PyString_Resize(&buf, outlen) < 0)
 			/* Oopsy, not so succesful after all. */
 			goto finally;
 	}
@@ -2358,7 +2353,7 @@
 	char *buf;
 	int len, n = -1, flags = 0, timeout;
 
-	if (!PyArg_ParseTuple(args, "s#|i:send", &buf, &len, &flags))
+	if (!PyArg_ParseTuple(args, "y#|i:send", &buf, &len, &flags))
 		return NULL;
 
 	if (!IS_SELECTABLE(s))
@@ -2399,7 +2394,7 @@
 	char *buf;
 	int len, n = -1, flags = 0, timeout;
 
-	if (!PyArg_ParseTuple(args, "s#|i:sendall", &buf, &len, &flags))
+	if (!PyArg_ParseTuple(args, "y#|i:sendall", &buf, &len, &flags))
 		return NULL;
 
 	if (!IS_SELECTABLE(s))
@@ -2454,9 +2449,9 @@
 	int addrlen, len, n = -1, flags, timeout;
 
 	flags = 0;
-	if (!PyArg_ParseTuple(args, "s#O:sendto", &buf, &len, &addro)) {
+	if (!PyArg_ParseTuple(args, "y#O:sendto", &buf, &len, &addro)) {
 		PyErr_Clear();
-		if (!PyArg_ParseTuple(args, "s#iO:sendto",
+		if (!PyArg_ParseTuple(args, "y#iO:sendto",
 				      &buf, &len, &flags, &addro))
 			return NULL;
 	}
@@ -3382,7 +3377,7 @@
     if (inet_aton != NULL) {
 #endif
 	if (inet_aton(ip_addr, &buf))
-		return PyBytes_FromStringAndSize((char *)(&buf),
+		return PyString_FromStringAndSize((char *)(&buf),
 						  sizeof(buf));
 
 	PyErr_SetString(socket_error,
@@ -3411,8 +3406,8 @@
 			return NULL;
 		}
 	}
-	return PyBytes_FromStringAndSize((char *) &packed_addr,
-					 sizeof(packed_addr));
+	return PyString_FromStringAndSize((char *) &packed_addr,
+                                          sizeof(packed_addr));
 
 #ifdef USE_INET_ATON_WEAKLINK
    }
@@ -3488,12 +3483,12 @@
 			"illegal IP address string passed to inet_pton");
 		return NULL;
 	} else if (af == AF_INET) {
-		return PyBytes_FromStringAndSize(packed,
-			sizeof(struct in_addr));
+		return PyString_FromStringAndSize(packed,
+                                                  sizeof(struct in_addr));
 #ifdef ENABLE_IPV6
 	} else if (af == AF_INET6) {
-		return PyBytes_FromStringAndSize(packed,
-			sizeof(struct in6_addr));
+		return PyString_FromStringAndSize(packed,
+                                                  sizeof(struct in6_addr));
 #endif
 	} else {
 		PyErr_SetString(socket_error, "unknown address family");