diff --git a/gcc/fortran/ChangeLog b/gcc/fortran/ChangeLog
index 414b6e3577ba..09750a4cf436 100644
--- a/gcc/fortran/ChangeLog
+++ b/gcc/fortran/ChangeLog
@@ -1,3 +1,7 @@
+2007-05-17  Tobias Burnus  <burnus@net-b.de>
+
+	* gfortran.texi (GFORTRAN_CONVERT_UNIT): Improve documentation.
+
 2007-05-16  Francois-Xavier Coudert  <fxcoudert@gcc.gnu.org>
 
 	PR fortran/31725
diff --git a/gcc/fortran/gfortran.texi b/gcc/fortran/gfortran.texi
index f61f787322ab..b8740db15638 100644
--- a/gcc/fortran/gfortran.texi
+++ b/gcc/fortran/gfortran.texi
@@ -611,7 +611,7 @@ By setting the @env{GFORTRAN_CONVERT_UNIT} variable, it is possible
 to change the representation of data for unformatted files.
 The syntax for the @env{GFORTRAN_CONVERT_UNIT} variable is:
 @smallexample
-GFORTRAN_CONVERT_UNIT: mode | mode ';' exception ;
+GFORTRAN_CONVERT_UNIT: mode | mode ';' exception | exception ;
 mode: 'native' | 'swap' | 'big_endian' | 'little_endian' ;
 exception: mode ':' unit_list | unit_list ;
 unit_list: unit_spec | unit_list unit_spec ;
@@ -668,6 +668,11 @@ data representation for unformatted files.  @xref{Runtime Options}, for
 setting a default data representation for the whole program.  The
 @code{CONVERT} specifier overrides the @option{-fconvert} compile options.
 
+@emph{Note that the values specified via the GFORTRAN_CONVERT_UNIT
+environment variable will override the CONVERT specifier in the
+open statement}.  This is to give control over data formats to
+users who do not have the source code of their program available.
+
 
 @c =====================================================================
 @c PART II: LANGUAGE REFERENCE