diff --git a/Python/Python-ast.c b/Python/Python-ast.c
index ae3a396..390ba15 100644
--- a/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@ -2,7 +2,7 @@
 
 
 /*
-   __version__ 53731.
+   __version__ 53866.
 
    This module must be committed separately after each AST grammar change;
    The __version__ number is set to the revision number of the commit
@@ -216,6 +216,10 @@
 static char *Str_fields[]={
         "s",
 };
+static PyTypeObject *Bytes_type;
+static char *Bytes_fields[]={
+        "s",
+};
 static PyTypeObject *Ellipsis_type;
 static PyTypeObject *Attribute_type;
 static char *Attribute_fields[]={
@@ -547,6 +551,8 @@
         if (!Num_type) return 0;
         Str_type = make_type("Str", expr_type, Str_fields, 1);
         if (!Str_type) return 0;
+        Bytes_type = make_type("Bytes", expr_type, Bytes_fields, 1);
+        if (!Bytes_type) return 0;
         Ellipsis_type = make_type("Ellipsis", expr_type, NULL, 0);
         if (!Ellipsis_type) return 0;
         Attribute_type = make_type("Attribute", expr_type, Attribute_fields, 3);
@@ -1587,6 +1593,27 @@
 }
 
 expr_ty
+Bytes(string s, int lineno, int col_offset, PyArena *arena)
+{
+        expr_ty p;
+        if (!s) {
+                PyErr_SetString(PyExc_ValueError,
+                                "field s is required for Bytes");
+                return NULL;
+        }
+        p = (expr_ty)PyArena_Malloc(arena, sizeof(*p));
+        if (!p) {
+                PyErr_NoMemory();
+                return NULL;
+        }
+        p->kind = Bytes_kind;
+        p->v.Bytes.s = s;
+        p->lineno = lineno;
+        p->col_offset = col_offset;
+        return p;
+}
+
+expr_ty
 Ellipsis(int lineno, int col_offset, PyArena *arena)
 {
         expr_ty p;
@@ -2550,6 +2577,15 @@
                         goto failed;
                 Py_DECREF(value);
                 break;
+        case Bytes_kind:
+                result = PyType_GenericNew(Bytes_type, NULL, NULL);
+                if (!result) goto failed;
+                value = ast2obj_string(o->v.Bytes.s);
+                if (!value) goto failed;
+                if (PyObject_SetAttrString(result, "s", value) == -1)
+                        goto failed;
+                Py_DECREF(value);
+                break;
         case Ellipsis_kind:
                 result = PyType_GenericNew(Ellipsis_type, NULL, NULL);
                 if (!result) goto failed;
@@ -3089,7 +3125,7 @@
         if (PyDict_SetItemString(d, "AST", (PyObject*)AST_type) < 0) return;
         if (PyModule_AddIntConstant(m, "PyCF_ONLY_AST", PyCF_ONLY_AST) < 0)
                 return;
-        if (PyModule_AddStringConstant(m, "__version__", "53731") < 0)
+        if (PyModule_AddStringConstant(m, "__version__", "53866") < 0)
                 return;
         if (PyDict_SetItemString(d, "mod", (PyObject*)mod_type) < 0) return;
         if (PyDict_SetItemString(d, "Module", (PyObject*)Module_type) < 0)
@@ -3155,6 +3191,7 @@
         if (PyDict_SetItemString(d, "Call", (PyObject*)Call_type) < 0) return;
         if (PyDict_SetItemString(d, "Num", (PyObject*)Num_type) < 0) return;
         if (PyDict_SetItemString(d, "Str", (PyObject*)Str_type) < 0) return;
+        if (PyDict_SetItemString(d, "Bytes", (PyObject*)Bytes_type) < 0) return;
         if (PyDict_SetItemString(d, "Ellipsis", (PyObject*)Ellipsis_type) < 0)
             return;
         if (PyDict_SetItemString(d, "Attribute", (PyObject*)Attribute_type) <
diff --git a/Python/ast.c b/Python/ast.c
index a7d5713..9d5caf8 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -33,8 +33,9 @@
 static expr_ty ast_for_call(struct compiling *, const node *, expr_ty);
 
 static PyObject *parsenumber(const char *);
-static PyObject *parsestr(const char *s, const char *encoding);
-static PyObject *parsestrplus(struct compiling *, const node *n);
+static PyObject *parsestr(const node *n, const char *encoding, int *bytesmode);
+static PyObject *parsestrplus(struct compiling *, const node *n,
+                              int *bytesmode);
 
 #ifndef LINENO
 #define LINENO(n)       ((n)->n_lineno)
@@ -1383,6 +1384,7 @@
        | '{' [dictsetmaker] '}' | NAME | NUMBER | STRING+
     */
     node *ch = CHILD(n, 0);
+    int bytesmode = 0;
     
     switch (TYPE(ch)) {
     case NAME:
@@ -1390,12 +1392,15 @@
            changed. */
         return Name(NEW_IDENTIFIER(ch), Load, LINENO(n), n->n_col_offset, c->c_arena);
     case STRING: {
-        PyObject *str = parsestrplus(c, n);
+        PyObject *str = parsestrplus(c, n, &bytesmode);
         if (!str)
             return NULL;
 
         PyArena_AddPyObject(c->c_arena, str);
-        return Str(str, LINENO(n), n->n_col_offset, c->c_arena);
+        if (bytesmode)
+            return Bytes(str, LINENO(n), n->n_col_offset, c->c_arena);
+        else
+            return Str(str, LINENO(n), n->n_col_offset, c->c_arena);
     }
     case NUMBER: {
         PyObject *pynum = parsenumber(STR(ch));
@@ -3254,9 +3259,10 @@
  * parsestr parses it, and returns the decoded Python string object.
  */
 static PyObject *
-parsestr(const char *s, const char *encoding)
+parsestr(const node *n, const char *encoding, int *bytesmode)
 {
         size_t len;
+        const char *s = STR(n);
         int quote = Py_CHARMASK(*s);
         int rawmode = 0;
         int need_encoding;
@@ -3267,6 +3273,10 @@
                         quote = *++s;
                         unicode = 1;
                 }
+                if (quote == 'b' || quote == 'B') {
+                        quote = *++s;
+                        *bytesmode = 1;
+                }             
                 if (quote == 'r' || quote == 'R') {
                         quote = *++s;
                         rawmode = 1;
@@ -3276,6 +3286,10 @@
                 PyErr_BadInternalCall();
                 return NULL;
         }
+        if (unicode && *bytesmode) {
+                ast_error(n, "string cannot be both bytes and unicode");
+                return NULL;
+        }
         s++;
         len = strlen(s);
         if (len > INT_MAX) {
@@ -3300,7 +3314,18 @@
                 return decode_unicode(s, len, rawmode, encoding);
         }
 #endif
-        need_encoding = (encoding != NULL &&
+        if (*bytesmode) {
+                /* Disallow non-ascii characters (but not escapes) */
+                const char *c;
+                for (c = s; *c; c++) {
+                        if (Py_CHARMASK(*c) >= 0x80) {
+                                ast_error(n, "bytes can only contain ASCII "
+                                          "literal characters.");
+                                return NULL;
+                        }
+                }
+        }
+        need_encoding = (!*bytesmode && encoding != NULL &&
                          strcmp(encoding, "utf-8") != 0 &&
                          strcmp(encoding, "iso-8859-1") != 0);
         if (rawmode || strchr(s, '\\') == NULL) {
@@ -3332,18 +3357,25 @@
  * pasting the intermediate results together.
  */
 static PyObject *
-parsestrplus(struct compiling *c, const node *n)
+parsestrplus(struct compiling *c, const node *n, int *bytesmode)
 {
         PyObject *v;
         int i;
         REQ(CHILD(n, 0), STRING);
-        if ((v = parsestr(STR(CHILD(n, 0)), c->c_encoding)) != NULL) {
+        v = parsestr(CHILD(n, 0), c->c_encoding, bytesmode);
+        if (v != NULL) {
                 /* String literal concatenation */
                 for (i = 1; i < NCH(n); i++) {
                         PyObject *s;
-                        s = parsestr(STR(CHILD(n, i)), c->c_encoding);
+                        int subbm = 0;
+                        s = parsestr(CHILD(n, i), c->c_encoding, &subbm);
                         if (s == NULL)
                                 goto onError;
+                        if (*bytesmode != subbm) {
+                                ast_error(n, "cannot mix bytes and nonbytes"
+                                          "literals");
+                                goto onError;
+                        }
                         if (PyString_Check(v) && PyString_Check(s)) {
                                 PyString_ConcatAndDel(&v, s);
                                 if (v == NULL)
diff --git a/Python/ceval.c b/Python/ceval.c
index 0194687..5ceb743 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -1885,6 +1885,19 @@
 			PUSH(x);
 			if (x != NULL) continue;
 			break;
+		
+		case MAKE_BYTES:
+			w = POP();
+			if (PyString_Check(w))
+				x = PyBytes_FromStringAndSize(
+					PyString_AS_STRING(w),
+					PyString_GET_SIZE(w));
+			else
+				x = NULL;
+			Py_DECREF(w);
+			PUSH(x);
+			if (x != NULL) continue;
+			break;
 
 		case LOAD_ATTR:
 			w = GETITEM(names, oparg);
diff --git a/Python/compile.c b/Python/compile.c
index 927569a..9655765 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -789,6 +789,8 @@
 			return 1-oparg;
 		case BUILD_MAP:
 			return 1;
+		case MAKE_BYTES:
+			return 0;
 		case LOAD_ATTR:
 			return 0;
 		case COMPARE_OP:
@@ -3077,6 +3079,10 @@
 	case Str_kind:
 		ADDOP_O(c, LOAD_CONST, e->v.Str.s, consts);
 		break;
+	case Bytes_kind:
+		ADDOP_O(c, LOAD_CONST, e->v.Bytes.s, consts);
+		ADDOP(c, MAKE_BYTES);
+		break;
 	case Ellipsis_kind:
 		ADDOP_O(c, LOAD_CONST, Py_Ellipsis, consts);
 		break;
@@ -3426,7 +3432,6 @@
 	return compiler_handle_subscr(c, kindname, ctx);
 }
 
-
 /* End of the compiler section, beginning of the assembler section */
 
 /* do depth-first search of basic block graph, starting with block.