diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7333e3e..81a9665 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -112,6 +112,7 @@ set(SOURCES
   src/stdio/fgetc.c
   src/stdio/fgetpos.c
   src/stdio/fgets.c
+  src/stdio/fileno.c
   src/stdio/fileutil.c
   src/stdio/fopen.c
   src/stdio/fprintf.c
diff --git a/STATUS b/STATUS
index d6016d6..15d2be2 100644
--- a/STATUS
+++ b/STATUS
@@ -99,6 +99,7 @@ TEST:       Function/symbol/macro needs to be tested
      7.19.5.4  freopen                       -
      7.19.5.5  setbuf                        -
      7.19.5.6  setvbuf                       -
+     (EXT)     fileno                        -
 
      7.19.6.1  fprintf                       -
      7.19.6.2  fscanf                        TODO
diff --git a/include/stdio.h b/include/stdio.h
index 205c33a..e489f7c 100644
--- a/include/stdio.h
+++ b/include/stdio.h
@@ -187,6 +187,7 @@ extern void setbuf(FILE * __restrict__ __fp, char * __restrict__ __buf);
 extern int setvbuf(FILE * __restrict__ __fp, char * __restrict__ __buf,
 	int __mode, size_t __size);
 
+/* Return the file descriptor associated with __fp. */
 extern int fileno(FILE *__fp);
 
 /*
diff --git a/src/stdio/fileno.c b/src/stdio/fileno.c
new file mode 100644
index 0000000..8d70343
--- /dev/null
+++ b/src/stdio/fileno.c
@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+int fileno(FILE *fp)
+{
+	return fp->fd;
+}