diff -r 815b88454e3e Lib/test/test_memoryio.py
--- a/Lib/test/test_memoryio.py	Fri Aug 31 17:14:31 2012 -0400
+++ b/Lib/test/test_memoryio.py	Sun Sep 02 14:56:47 2012 +0100
@@ -347,6 +347,17 @@
             memio = self.ioclass()
             memio.foo = 1
 
+    def test_unusable_after_close(self):
+        # Test case for issue #15841
+        memio = self.ioclass()
+        self.assertTrue(memio.readable())
+        self.assertTrue(memio.writable())
+        self.assertTrue(memio.seekable())
+        memio.close()
+        self.assertFalse(memio.readable())
+        self.assertFalse(memio.writable())
+        self.assertFalse(memio.seekable())
+
     def test_pickling(self):
         buf = self.buftype("1234567890")
         memio = self.ioclass(buf)
diff -r 815b88454e3e Modules/_io/bytesio.c
--- a/Modules/_io/bytesio.c	Fri Aug 31 17:14:31 2012 -0400
+++ b/Modules/_io/bytesio.c	Sun Sep 02 14:56:47 2012 +0100
@@ -121,7 +121,7 @@
 }
 
 /* Internal routine for writing a string of bytes to the buffer of a BytesIO
-   object. Returns the number of bytes wrote, or -1 on error. */
+   object. Returns the number of bytes written, or -1 on error. */
 static Py_ssize_t
 write_bytes(bytesio *self, const char *bytes, Py_ssize_t len)
 {
@@ -171,11 +171,22 @@
     }
 }
 
+PyDoc_STRVAR(readable_doc,
+"readable() -> Bool. Returns True if the IO object can be read.");
+
+PyDoc_STRVAR(writable_doc,
+"writable() -> Bool. Returns True if the IO object can be written.");
+
+PyDoc_STRVAR(seekable_doc,
+"seekable() -> Bool. Returns True if IO object can be seeked.");
+
 /* Generic getter for the writable, readable and seekable properties */
 static PyObject *
-return_true(bytesio *self)
+return_not_closed(bytesio *self)
 {
-    Py_RETURN_TRUE;
+    if (self->buf)
+        Py_RETURN_TRUE;
+    Py_RETURN_FALSE;
 }
 
 PyDoc_STRVAR(flush_doc,
@@ -867,9 +878,9 @@
 };
 
 static struct PyMethodDef bytesio_methods[] = {
-    {"readable",   (PyCFunction)return_true,        METH_NOARGS, NULL},
-    {"seekable",   (PyCFunction)return_true,        METH_NOARGS, NULL},
-    {"writable",   (PyCFunction)return_true,        METH_NOARGS, NULL},
+    {"readable",   (PyCFunction)return_not_closed,  METH_NOARGS, readable_doc},
+    {"seekable",   (PyCFunction)return_not_closed,  METH_NOARGS, seekable_doc},
+    {"writable",   (PyCFunction)return_not_closed,  METH_NOARGS, writable_doc},
     {"close",      (PyCFunction)bytesio_close,      METH_NOARGS, close_doc},
     {"flush",      (PyCFunction)bytesio_flush,      METH_NOARGS, flush_doc},
     {"isatty",     (PyCFunction)bytesio_isatty,     METH_NOARGS, isatty_doc},
diff -r 815b88454e3e Modules/_io/stringio.c
--- a/Modules/_io/stringio.c	Fri Aug 31 17:14:31 2012 -0400
+++ b/Modules/_io/stringio.c	Sun Sep 02 14:56:47 2012 +0100
@@ -760,10 +760,22 @@
 }
 
 /* Properties and pseudo-properties */
+
+PyDoc_STRVAR(readable_doc,
+"readable() -> Bool. Returns True if the IO object can be read.");
+
+PyDoc_STRVAR(writable_doc,
+"writable() -> Bool. Returns True if the IO object can be written.");
+
+PyDoc_STRVAR(seekable_doc,
+"seekable() -> Bool. Returns True if IO object can be seeked.");
+
 static PyObject *
 stringio_seekable(stringio *self, PyObject *args)
 {
     CHECK_INITIALIZED(self);
+    if (self->closed)
+       Py_RETURN_FALSE;
     Py_RETURN_TRUE;
 }
 
@@ -771,6 +783,8 @@
 stringio_readable(stringio *self, PyObject *args)
 {
     CHECK_INITIALIZED(self);
+    if (self->closed)
+       Py_RETURN_FALSE;
     Py_RETURN_TRUE;
 }
 
@@ -778,6 +792,8 @@
 stringio_writable(stringio *self, PyObject *args)
 {
     CHECK_INITIALIZED(self);
+    if (self->closed)
+       Py_RETURN_FALSE;
     Py_RETURN_TRUE;
 }
 
@@ -956,9 +972,9 @@
     {"seek",     (PyCFunction)stringio_seek,     METH_VARARGS, stringio_seek_doc},
     {"write",    (PyCFunction)stringio_write,    METH_O,       stringio_write_doc},
 
-    {"seekable", (PyCFunction)stringio_seekable, METH_NOARGS},
-    {"readable", (PyCFunction)stringio_readable, METH_NOARGS},
-    {"writable", (PyCFunction)stringio_writable, METH_NOARGS},
+    {"seekable", (PyCFunction)stringio_seekable, METH_NOARGS, seekable_doc},
+    {"readable", (PyCFunction)stringio_readable, METH_NOARGS, readable_doc},
+    {"writable", (PyCFunction)stringio_writable, METH_NOARGS, writable_doc},
 
     {"__getstate__", (PyCFunction)stringio_getstate, METH_NOARGS},
     {"__setstate__", (PyCFunction)stringio_setstate, METH_O},