diff --git Doc/library/os.rst Doc/library/os.rst
index 0547154..5c34cb3 100644
--- Doc/library/os.rst
+++ Doc/library/os.rst
@@ -437,6 +437,9 @@ process will then be assigned 3, 4, 5, and so forth.  The name "file descriptor"
 is slightly deceptive; on Unix platforms, sockets and pipes are also referenced
 by file descriptors.
 
+For these functions, the file descriptor can either be an integer, or an object
+with a fileno() method which returns the actual file descriptor.
+
 
 .. function:: close(fd)
 
@@ -552,7 +555,6 @@ by file descriptors.
    Return ``True`` if the file descriptor *fd* is open and connected to a
    tty(-like) device, else ``False``. Availability: Unix.
 
-
 .. function:: lseek(fd, pos, how)
 
    Set the current position of file descriptor *fd* to position *pos*, modified
@@ -561,7 +563,6 @@ by file descriptors.
    current position; :const:`os.SEEK_END` or ``2`` to set it relative to the end of
    the file. Availability: Unix, Windows.
 
-
 .. function:: open(file, flags[, mode])
 
    Open the file *file* and set various flags according to *flags* and possibly
@@ -617,7 +618,6 @@ by file descriptors.
    Return the process group associated with the terminal given by *fd* (an open
    file descriptor as returned by :func:`os.open`). Availability: Unix.
 
-
 .. function:: tcsetpgrp(fd, pg)
 
    Set the process group associated with the terminal given by *fd* (an open file
diff --git Lib/test/test_posix.py Lib/test/test_posix.py
index fa1abe3..c60af24 100644
--- Lib/test/test_posix.py
+++ Lib/test/test_posix.py
@@ -116,6 +116,7 @@ class PosixTester(unittest.TestCase):
             fp = open(support.TESTFN)
             try:
                 self.assertTrue(posix.fstatvfs(fp.fileno()))
+                self.assertTrue(posix.fstatvfs(fp))
             finally:
                 fp.close()
 
@@ -129,6 +130,14 @@ class PosixTester(unittest.TestCase):
                 posix.ftruncate(fp.fileno(), 0)
             finally:
                 fp.close()
+            fp = open(support.TESTFN, 'w+')
+            try:
+                fp.write('test')
+                fp.flush()
+                posix.ftruncate(fp, 0)
+            finally:
+                fp.close()
+
 
     def test_dup(self):
         if hasattr(posix, 'dup'):
@@ -139,6 +148,14 @@ class PosixTester(unittest.TestCase):
                 os.close(fd)
             finally:
                 fp.close()
+            fp = open(support.TESTFN)
+            try:
+                fd = posix.dup(fp)
+                self.assert_(isinstance(fd, int))
+                os.close(fd)
+            finally:
+                fp.close()
+
 
     def test_confstr(self):
         if hasattr(posix, 'confstr'):
@@ -191,6 +208,7 @@ class PosixTester(unittest.TestCase):
             fp = open(support.TESTFN)
             try:
                 self.assertTrue(posix.fstat(fp.fileno()))
+                self.assertTrue(posix.fstat(fp))
             finally:
                 fp.close()
 
diff --git Modules/posixmodule.c Modules/posixmodule.c
index 5076d3b..e1c8587 100644
--- Modules/posixmodule.c
+++ Modules/posixmodule.c
@@ -1796,9 +1796,13 @@ descriptor fd.");
 static PyObject *
 posix_fchmod(PyObject *self, PyObject *args)
 {
+	PyObject *fdobj;
 	int fd, mode, res;
-	if (!PyArg_ParseTuple(args, "ii:fchmod", &fd, &mode))
+	if (!PyArg_ParseTuple(args, "Oi:fchmod", &fdobj, &mode))
 		return NULL;
+	fd = PyObject_AsFileDescriptor(fdobj);
+	if (fd == -1)
+		return NULL; /* Rely on AsFileDescriptor's error handling */
 	Py_BEGIN_ALLOW_THREADS
 	res = fchmod(fd, mode);
 	Py_END_ALLOW_THREADS
@@ -1971,11 +1975,15 @@ fd to the numeric uid and gid.");
 static PyObject *
 posix_fchown(PyObject *self, PyObject *args)
 {
+	PyObject *fdobj;
 	int fd;
 	long uid, gid;
 	int res;
-	if (!PyArg_ParseTuple(args, "ill:chown", &fd, &uid, &gid))
+	if (!PyArg_ParseTuple(args, "Oll:chown", &fdobj, &uid, &gid))
 		return NULL;
+	if (fd == -1)
+		return NULL; /* Rely on AsFileDescriptor's error handling */
+	fd = PyObject_AsFileDescriptor(fdobj);
 	Py_BEGIN_ALLOW_THREADS
 	res = fchown(fd, (uid_t) uid, (gid_t) gid);
 	Py_END_ALLOW_THREADS
@@ -4836,10 +4844,14 @@ Return the process group associated with the terminal given by a fd.");
 static PyObject *
 posix_tcgetpgrp(PyObject *self, PyObject *args)
 {
+	PyObject *fdobj;
 	int fd;
 	pid_t pgid;
-	if (!PyArg_ParseTuple(args, "i:tcgetpgrp", &fd))
+	if (!PyArg_ParseTuple(args, "O:tcgetpgrp", &fdobj))
 		return NULL;
+	fd = PyObject_AsFileDescriptor(fdobj);
+	if (fd == -1)
+		return NULL; /* Rely on AsFileDescriptor's error handling */
 	pgid = tcgetpgrp(fd);
 	if (pgid < 0)
 		return posix_error();
@@ -4856,10 +4868,14 @@ Set the process group associated with the terminal given by a fd.");
 static PyObject *
 posix_tcsetpgrp(PyObject *self, PyObject *args)
 {
+	PyObject *fdobj;
 	int fd;
 	pid_t pgid;
-	if (!PyArg_ParseTuple(args, "i" _Py_PARSE_PID ":tcsetpgrp", &fd, &pgid))
+	if (!PyArg_ParseTuple(args, "O" _Py_PARSE_PID ":tcsetpgrp", &fdobj, &pgid))
 		return NULL;
+	fd = PyObject_AsFileDescriptor(fdobj);
+	if (fd == -1)
+		return NULL; /* Rely on AsFileDescriptor's error handling */
 	if (tcsetpgrp(fd, pgid) < 0)
 		return posix_error();
 	Py_INCREF(Py_None);
@@ -4921,9 +4937,12 @@ Close a file descriptor (for low level IO).");
 static PyObject *
 posix_close(PyObject *self, PyObject *args)
 {
+	PyObject *fdobj;
 	int fd, res;
-	if (!PyArg_ParseTuple(args, "i:close", &fd))
+	if (!PyArg_ParseTuple(args, "O:close", &fdobj))
 		return NULL;
+	fd = PyObject_AsFileDescriptor(fdobj);
+	/* Rely on PyVerify to detect error cases */
 	if (!_PyVerify_fd(fd))
 		return posix_error();
 	Py_BEGIN_ALLOW_THREADS
@@ -4962,9 +4981,12 @@ Return a duplicate of a file descriptor.");
 static PyObject *
 posix_dup(PyObject *self, PyObject *args)
 {
+	PyObject *fdobj;
 	int fd;
-	if (!PyArg_ParseTuple(args, "i:dup", &fd))
+	if (!PyArg_ParseTuple(args, "O:dup", &fdobj))
 		return NULL;
+	fd = PyObject_AsFileDescriptor(fdobj);
+	/* Rely on PyVerify to detect error cases */
 	if (!_PyVerify_fd(fd))
 		return posix_error();
 	Py_BEGIN_ALLOW_THREADS
@@ -4983,9 +5005,12 @@ Duplicate file descriptor.");
 static PyObject *
 posix_dup2(PyObject *self, PyObject *args)
 {
+	PyObject *fdobj1, *fdobj2;
 	int fd, fd2, res;
-	if (!PyArg_ParseTuple(args, "ii:dup2", &fd, &fd2))
+	if (!PyArg_ParseTuple(args, "OO:dup2", &fdobj1, &fdobj2))
 		return NULL;
+	fd  = PyObject_AsFileDescriptor(fdobj1);
+	fd2 = PyObject_AsFileDescriptor(fdobj2);
 	if (!_PyVerify_fd_dup2(fd, fd2))
 		return posix_error();
 	Py_BEGIN_ALLOW_THREADS
@@ -5011,9 +5036,13 @@ posix_lseek(PyObject *self, PyObject *args)
 #else
 	off_t pos, res;
 #endif
+	PyObject *fdobj;
 	PyObject *posobj;
-	if (!PyArg_ParseTuple(args, "iOi:lseek", &fd, &posobj, &how))
+	if (!PyArg_ParseTuple(args, "OOi:lseek", &fdobj, &posobj, &how))
 		return NULL;
+	fd = PyObject_AsFileDescriptor(fdobj);
+	if (fd == -1)
+		return NULL; /* Rely on AsFileDescriptor's error handling */
 #ifdef SEEK_SET
 	/* Turn 0, 1, 2 into SEEK_{SET,CUR,END} */
 	switch (how) {
@@ -5059,11 +5088,15 @@ Read a file descriptor.");
 static PyObject *
 posix_read(PyObject *self, PyObject *args)
 {
+	PyObject *fdobj;
 	int fd, size;
         Py_ssize_t n;
 	PyObject *buffer;
-	if (!PyArg_ParseTuple(args, "ii:read", &fd, &size))
+	if (!PyArg_ParseTuple(args, "Oi:read", &fdobj, &size))
 		return NULL;
+	fd = PyObject_AsFileDescriptor(fdobj);
+	if (fd == -1)
+		return NULL; /* Rely on AsFileDescriptor's error handling */
 	if (size < 0) {
 		errno = EINVAL;
 		return posix_error();
@@ -5093,12 +5126,15 @@ Write a string to a file descriptor.");
 static PyObject *
 posix_write(PyObject *self, PyObject *args)
 {
+	PyObject *fdobj;
 	Py_buffer pbuf;
 	int fd;
 	Py_ssize_t size;
 
-	if (!PyArg_ParseTuple(args, "iy*:write", &fd, &pbuf))
+	if (!PyArg_ParseTuple(args, "Oy*:write", &fdobj, &pbuf))
 		return NULL;
+	fd = PyObject_AsFileDescriptor(fdobj);
+	/* Rely on PyVerify to detect error cases */
 	if (!_PyVerify_fd(fd))
 		return posix_error();
 	Py_BEGIN_ALLOW_THREADS
@@ -5118,11 +5154,15 @@ Like stat(), but for an open file descriptor.");
 static PyObject *
 posix_fstat(PyObject *self, PyObject *args)
 {
-	int fd;
+	PyObject *fdobj;
 	STRUCT_STAT st;
 	int res;
-	if (!PyArg_ParseTuple(args, "i:fstat", &fd))
+        int fd;
+	if (!PyArg_ParseTuple(args, "O:fstat", &fdobj))
 		return NULL;
+        fd = PyObject_AsFileDescriptor(fdobj);
+        if (fd == -1)
+                return NULL; /* Rely on AsFileDescriptor's error handling */
 #ifdef __VMS
         /* on OpenVMS we must ensure that all bytes are written to the file */
         fsync(fd);
@@ -5151,9 +5191,12 @@ connected to the slave end of a terminal.");
 static PyObject *
 posix_isatty(PyObject *self, PyObject *args)
 {
+	PyObject *fdobj;
 	int fd;
-	if (!PyArg_ParseTuple(args, "i:isatty", &fd))
+	if (!PyArg_ParseTuple(args, "O:isatty", &fdobj))
 		return NULL;
+	fd = PyObject_AsFileDescriptor(fdobj);
+	/* Rely on PyVerify to detect error cases */
 	if (!_PyVerify_fd(fd))
 		return PyBool_FromLong(0);
 	return PyBool_FromLong(isatty(fd));
@@ -5310,13 +5353,17 @@ Truncate a file to a specified length.");
 static PyObject *
 posix_ftruncate(PyObject *self, PyObject *args)
 {
+	PyObject *fdobj;
 	int fd;
 	off_t length;
 	int res;
 	PyObject *lenobj;
 
-	if (!PyArg_ParseTuple(args, "iO:ftruncate", &fd, &lenobj))
+	if (!PyArg_ParseTuple(args, "OO:ftruncate", &fdobj, &lenobj))
 		return NULL;
+	fd = PyObject_AsFileDescriptor(fdobj);
+	if (fd == -1)
+		return NULL; /* Rely on AsFileDescriptor's error handling */
 
 #if !defined(HAVE_LARGEFILE_SUPPORT)
 	length = PyLong_AsLong(lenobj);
@@ -5706,11 +5753,15 @@ Perform an fstatvfs system call on the given fd.");
 static PyObject *
 posix_fstatvfs(PyObject *self, PyObject *args)
 {
+	PyObject *fdobj;
 	int fd, res;
 	struct statvfs st;
 
-	if (!PyArg_ParseTuple(args, "i:fstatvfs", &fd))
+	if (!PyArg_ParseTuple(args, "O:fstatvfs", &fdobj))
 		return NULL;
+	fd = PyObject_AsFileDescriptor(fdobj);
+	if (fd == -1)
+		return NULL; /* Rely on AsFileDescriptor's error handling */
 	Py_BEGIN_ALLOW_THREADS
 	res = fstatvfs(fd, &st);
 	Py_END_ALLOW_THREADS
@@ -5878,10 +5929,15 @@ static PyObject *
 posix_fpathconf(PyObject *self, PyObject *args)
 {
     PyObject *result = NULL;
+    PyObject *fdobj;
     int name, fd;
 
-    if (PyArg_ParseTuple(args, "iO&:fpathconf", &fd,
+    if (PyArg_ParseTuple(args, "OO&:fpathconf", &fdobj,
                          conv_path_confname, &name)) {
+
+      fd = PyObject_AsFileDescriptor(fdobj);
+      if (fd == -1)
+         return NULL; /* Rely on AsFileDescriptor's error handling */
         long limit;
 
         errno = 0;