diff --git a/Modules/zlibmodule.c b/Modules/zlibmodule.c
index 4f78dbc..590ab5f 100644
--- a/Modules/zlibmodule.c
+++ b/Modules/zlibmodule.c
@@ -96,12 +96,12 @@
     if (self == NULL)
 	return NULL;
     self->is_initialised = 0;
-    self->unused_data = PyString_FromString("");
+    self->unused_data = PyBytes_FromString("");
     if (self->unused_data == NULL) {
 	Py_DECREF(self);
 	return NULL;
     }
-    self->unconsumed_tail = PyString_FromString("");
+    self->unconsumed_tail = PyBytes_FromString("");
     if (self->unconsumed_tail == NULL) {
 	Py_DECREF(self);
 	return NULL;
@@ -174,7 +174,7 @@
 
     err=deflateEnd(&zst);
     if (err == Z_OK)
-	ReturnVal = PyString_FromStringAndSize((char *)output,
+	ReturnVal = PyBytes_FromStringAndSize((char *)output,
 					       zst.total_out);
     else
 	zlib_error(zst, err, "while finishing compression");
@@ -211,12 +211,12 @@
     zst.avail_in = length;
     zst.avail_out = r_strlen;
 
-    if (!(result_str = PyString_FromStringAndSize(NULL, r_strlen)))
+    if (!(result_str = PyBytes_FromStringAndSize(NULL, r_strlen)))
 	return NULL;
 
     zst.zalloc = (alloc_func)NULL;
     zst.zfree = (free_func)Z_NULL;
-    zst.next_out = (Byte *)PyString_AS_STRING(result_str);
+    zst.next_out = (Byte *)PyBytes_AS_STRING(result_str);
     zst.next_in = (Byte *)input;
     err = inflateInit2(&zst, wsize);
 
@@ -256,11 +256,11 @@
 	    /* fall through */
 	case(Z_OK):
 	    /* need more memory */
-	    if (_PyString_Resize(&result_str, r_strlen << 1) < 0) {
+	    if (_PyBytes_Resize(&result_str, r_strlen << 1) < 0) {
 		inflateEnd(&zst);
 		goto error;
 	    }
-	    zst.next_out = (unsigned char *)PyString_AS_STRING(result_str) \
+	    zst.next_out = (unsigned char *)PyBytes_AS_STRING(result_str) \
 		+ r_strlen;
 	    zst.avail_out = r_strlen;
 	    r_strlen = r_strlen << 1;
@@ -278,7 +278,7 @@
 	goto error;
     }
 
-    _PyString_Resize(&result_str, zst.total_out);
+    _PyBytes_Resize(&result_str, zst.total_out);
     return result_str;
 
  error:
@@ -400,7 +400,7 @@
     if (!PyArg_ParseTuple(args, "s#:compress", &input, &inplen))
 	return NULL;
 
-    if (!(RetVal = PyString_FromStringAndSize(NULL, length)))
+    if (!(RetVal = PyBytes_FromStringAndSize(NULL, length)))
 	return NULL;
 
     ENTER_ZLIB
@@ -409,7 +409,7 @@
     self->zst.avail_in = inplen;
     self->zst.next_in = input;
     self->zst.avail_out = length;
-    self->zst.next_out = (unsigned char *)PyString_AS_STRING(RetVal);
+    self->zst.next_out = (unsigned char *)PyBytes_AS_STRING(RetVal);
 
     Py_BEGIN_ALLOW_THREADS
     err = deflate(&(self->zst), Z_NO_FLUSH);
@@ -418,9 +418,9 @@
     /* while Z_OK and the output buffer is full, there might be more output,
        so extend the output buffer and try again */
     while (err == Z_OK && self->zst.avail_out == 0) {
-	if (_PyString_Resize(&RetVal, length << 1) < 0)
+	if (_PyBytes_Resize(&RetVal, length << 1) < 0)
 	    goto error;
-	self->zst.next_out = (unsigned char *)PyString_AS_STRING(RetVal) \
+	self->zst.next_out = (unsigned char *)PyBytes_AS_STRING(RetVal) \
 	    + length;
 	self->zst.avail_out = length;
 	length = length << 1;
@@ -440,7 +440,7 @@
 	RetVal = NULL;
 	goto error;
     }
-    _PyString_Resize(&RetVal, self->zst.total_out - start_total_out);
+    _PyBytes_Resize(&RetVal, self->zst.total_out - start_total_out);
 
  error:
     LEAVE_ZLIB
@@ -479,7 +479,7 @@
     /* limit amount of data allocated to max_length */
     if (max_length && length > max_length)
 	length = max_length;
-    if (!(RetVal = PyString_FromStringAndSize(NULL, length)))
+    if (!(RetVal = PyBytes_FromStringAndSize(NULL, length)))
 	return NULL;
 
     ENTER_ZLIB
@@ -488,7 +488,7 @@
     self->zst.avail_in = inplen;
     self->zst.next_in = input;
     self->zst.avail_out = length;
-    self->zst.next_out = (unsigned char *)PyString_AS_STRING(RetVal);
+    self->zst.next_out = (unsigned char *)PyBytes_AS_STRING(RetVal);
 
     Py_BEGIN_ALLOW_THREADS
     err = inflate(&(self->zst), Z_SYNC_FLUSH);
@@ -510,9 +510,9 @@
 	if (max_length && length > max_length)
 	    length = max_length;
 
-	if (_PyString_Resize(&RetVal, length) < 0)
+	if (_PyBytes_Resize(&RetVal, length) < 0)
 	    goto error;
-	self->zst.next_out = (unsigned char *)PyString_AS_STRING(RetVal) \
+	self->zst.next_out = (unsigned char *)PyBytes_AS_STRING(RetVal) \
 	    + old_length;
 	self->zst.avail_out = length - old_length;
 
@@ -525,7 +525,7 @@
        of specified size. Return the unconsumed tail in an attribute.*/
     if(max_length) {
 	Py_DECREF(self->unconsumed_tail);
-	self->unconsumed_tail = PyString_FromStringAndSize((char *)self->zst.next_in,
+	self->unconsumed_tail = PyBytes_FromStringAndSize((char *)self->zst.next_in,
 							   self->zst.avail_in);
 	if(!self->unconsumed_tail) {
 	    Py_DECREF(RetVal);
@@ -542,7 +542,7 @@
     */
     if (err == Z_STREAM_END) {
 	Py_XDECREF(self->unused_data);  /* Free original empty string */
-	self->unused_data = PyString_FromStringAndSize(
+	self->unused_data = PyBytes_FromStringAndSize(
 	    (char *)self->zst.next_in, self->zst.avail_in);
 	if (self->unused_data == NULL) {
 	    Py_DECREF(RetVal);
@@ -559,7 +559,7 @@
 	goto error;
     }
 
-    _PyString_Resize(&RetVal, self->zst.total_out - start_total_out);
+    _PyBytes_Resize(&RetVal, self->zst.total_out - start_total_out);
 
  error:
     LEAVE_ZLIB
@@ -589,10 +589,10 @@
     /* Flushing with Z_NO_FLUSH is a no-op, so there's no point in
        doing any work at all; just return an empty string. */
     if (flushmode == Z_NO_FLUSH) {
-	return PyString_FromStringAndSize(NULL, 0);
+	return PyBytes_FromStringAndSize(NULL, 0);
     }
 
-    if (!(RetVal = PyString_FromStringAndSize(NULL, length)))
+    if (!(RetVal = PyBytes_FromStringAndSize(NULL, length)))
 	return NULL;
 
     ENTER_ZLIB
@@ -600,7 +600,7 @@
     start_total_out = self->zst.total_out;
     self->zst.avail_in = 0;
     self->zst.avail_out = length;
-    self->zst.next_out = (unsigned char *)PyString_AS_STRING(RetVal);
+    self->zst.next_out = (unsigned char *)PyBytes_AS_STRING(RetVal);
 
     Py_BEGIN_ALLOW_THREADS
     err = deflate(&(self->zst), flushmode);
@@ -609,9 +609,9 @@
     /* while Z_OK and the output buffer is full, there might be more output,
        so extend the output buffer and try again */
     while (err == Z_OK && self->zst.avail_out == 0) {
-	if (_PyString_Resize(&RetVal, length << 1) < 0)
+	if (_PyBytes_Resize(&RetVal, length << 1) < 0)
 	    goto error;
-	self->zst.next_out = (unsigned char *)PyString_AS_STRING(RetVal) \
+	self->zst.next_out = (unsigned char *)PyBytes_AS_STRING(RetVal) \
 	    + length;
 	self->zst.avail_out = length;
 	length = length << 1;
@@ -646,7 +646,7 @@
 	goto error;
     }
 
-    _PyString_Resize(&RetVal, self->zst.total_out - start_total_out);
+    _PyBytes_Resize(&RetVal, self->zst.total_out - start_total_out);
 
  error:
     LEAVE_ZLIB
@@ -778,7 +778,7 @@
 	PyErr_SetString(PyExc_ValueError, "length must be greater than zero");
 	return NULL;
     }
-    if (!(retval = PyString_FromStringAndSize(NULL, length)))
+    if (!(retval = PyBytes_FromStringAndSize(NULL, length)))
 	return NULL;
 
 
@@ -786,7 +786,7 @@
 
     start_total_out = self->zst.total_out;
     self->zst.avail_out = length;
-    self->zst.next_out = (Byte *)PyString_AS_STRING(retval);
+    self->zst.next_out = (Byte *)PyBytes_AS_STRING(retval);
 
     Py_BEGIN_ALLOW_THREADS
     err = inflate(&(self->zst), Z_FINISH);
@@ -795,9 +795,9 @@
     /* while Z_OK and the output buffer is full, there might be more output,
        so extend the output buffer and try again */
     while ((err == Z_OK || err == Z_BUF_ERROR) && self->zst.avail_out == 0) {
-	if (_PyString_Resize(&retval, length << 1) < 0)
+	if (_PyBytes_Resize(&retval, length << 1) < 0)
 	    goto error;
-	self->zst.next_out = (Byte *)PyString_AS_STRING(retval) + length;
+	self->zst.next_out = (Byte *)PyBytes_AS_STRING(retval) + length;
 	self->zst.avail_out = length;
 	length = length << 1;
 
@@ -819,7 +819,7 @@
 	    goto error;
 	}
     }
-    _PyString_Resize(&retval, self->zst.total_out - start_total_out);
+    _PyBytes_Resize(&retval, self->zst.total_out - start_total_out);
 
 error:
 
@@ -1027,7 +1027,7 @@
     PyModule_AddIntConstant(m, "Z_SYNC_FLUSH", Z_SYNC_FLUSH);
     PyModule_AddIntConstant(m, "Z_FULL_FLUSH", Z_FULL_FLUSH);
 
-    ver = PyString_FromString(ZLIB_VERSION);
+    ver = PyBytes_FromString(ZLIB_VERSION);
     if (ver != NULL)
 	PyModule_AddObject(m, "ZLIB_VERSION", ver);