diff --git a/Lib/fileinput.py b/Lib/fileinput.py
index 5c06627..692eeea 100644
--- a/Lib/fileinput.py
+++ b/Lib/fileinput.py
@@ -73,7 +73,6 @@
 
 - optional getopt argument processing
 - specify open mode ('r' or 'rb')
-- fileno()
 - isatty()
 - read(), read(size), even readlines()
 
@@ -153,6 +152,15 @@
         raise RuntimeError, "no active input()"
     return _state.filelineno()
 
+def fileno():
+    """
+    Return the file number of the current file. When no file is currently
+    opened, returns -1.
+    """
+    if not _state:
+        raise RuntimeError, "no active input()"
+    return _state.fileno()
+
 def isfirstline():
     """
     Returns true the line just read is the first line of its file,
@@ -175,8 +183,9 @@
     """class FileInput([files[, inplace[, backup]]])
 
     Class FileInput is the implementation of the module; its methods
-    filename(), lineno(), fileline(), isfirstline(), isstdin(), nextfile()
-    and close() correspond to the functions of the same name in the module.
+    filename(), lineno(), fileline(), isfirstline(), isstdin(), fileno(),
+    nextfile() and close() correspond to the functions of the same name
+    in the module.
     In addition it has a readline() method which returns the next
     input line, and a __getitem__() method which implements the
     sequence behavior. The sequence must be accessed in strictly
@@ -334,6 +343,15 @@
     def filelineno(self):
         return self._filelineno
 
+    def fileno(self):
+        if self._file:
+            try:
+                return self._file.fileno()
+            except ValueError:
+                return -1
+        else:
+            return -1
+
     def isfirstline(self):
         return self._filelineno == 1
 
diff --git a/Lib/test/test_fileinput.py b/Lib/test/test_fileinput.py
index 285573c..be4cb8e 100644
--- a/Lib/test/test_fileinput.py
+++ b/Lib/test/test_fileinput.py
@@ -167,3 +167,19 @@
     verify(lines == ["A\n", "B"])
 finally:
     remove_tempfiles(t1)
+
+if verbose:
+    print "16. fileno()"
+try:
+    t1 = writeTmp(1, ["A\nB"])
+    t2 = writeTmp(2, ["C\nD"])
+    fi = FileInput(files=(t1, t2))
+    verify(fi.fileno() == -1)
+    line = fi.next()
+    verify(fi.fileno() != -1)
+    fi.nextfile()
+    verify(fi.fileno() == -1)
+    line = list(fi)
+    verify(fi.fileno() == -1)
+finally:
+    remove_tempfiles(t1, t2)