diff --git a/NEWS b/NEWS
index e9a8c3a4c..ee8ec750c 100644
--- a/NEWS
+++ b/NEWS
@@ -99,7 +99,7 @@ manual.
 
 ** Add variable-unset!
     
-FIXME: document.
+See "Variables" in the manual, for more details.
 
 ** Command line additions
 
diff --git a/doc/ref/api-modules.texi b/doc/ref/api-modules.texi
index 790cca64d..709aa7312 100644
--- a/doc/ref/api-modules.texi
+++ b/doc/ref/api-modules.texi
@@ -1074,6 +1074,11 @@ Set the value of the variable @var{var} to @var{val}.
 value. Return an unspecified value.
 @end deffn
 
+@deffn {Scheme Procedure} variable-unset! var
+@deffnx {C Function} scm_variable_unset_x (var)
+Unset the value of the variable @var{var}, leaving @var{var} unbound.
+@end deffn
+
 @deffn {Scheme Procedure} variable? obj
 @deffnx {C Function} scm_variable_p (obj)
 Return @code{#t} iff @var{obj} is a variable object, else