diff --git a/libs/mod_neko/cgi.c b/libs/mod_neko/cgi.c
index 017b8a27..388bafc1 100644
--- a/libs/mod_neko/cgi.c
+++ b/libs/mod_neko/cgi.c
@@ -188,6 +188,23 @@ static value set_header( value s, value k ) {
 	return val_true;
 }
 
+/**
+	add_header : name:string -> val:string -> void
+	<doc>Add a HTTP header value</doc>
+**/
+static value add_header( value s, value k ) {
+	mcontext *c = CONTEXT();
+	val_check(s,string);
+	val_check(k,string);
+	HEADERS_NOT_SENT("Header");
+	if( strcmpi(val_string(s),"Content-Type") == 0 ) {
+		c->content_type = alloc_string(val_string(k));
+		c->r->content_type = val_string(c->content_type);
+	} else
+		ap_table_add(c->r->headers_out,val_string(s),val_string(k));
+	return val_true;
+}
+
 /**
 	get_client_header : name:string -> string?
 	<doc>Get a HTTP header sent by the client</doc>
@@ -594,6 +611,7 @@ DEFINE_PRIM(get_params,0);
 DEFINE_PRIM(get_params_string,0);
 DEFINE_PRIM(get_post_data,0);
 DEFINE_PRIM(set_header,2);
+DEFINE_PRIM(add_header,2);
 DEFINE_PRIM(set_return_code,1);
 DEFINE_PRIM(get_client_header,1);
 DEFINE_PRIM(get_client_headers,0);
diff --git a/src/tools/WebServer.nml b/src/tools/WebServer.nml
index 60a38247..006a94c9 100644
--- a/src/tools/WebServer.nml
+++ b/src/tools/WebServer.nml
@@ -333,6 +333,12 @@ function set_header(c,n,v) {
 	c.headers := (n,v) :: List.filter (function((n2,_)) { n != n2 }) c.headers;
 }
 
+
+function add_header(c,n,v) {
+	headers_not_sent c n;
+	c.headers := (n,v) :: c.headers;
+}
+
 var cur_client : client option ref = &None;
 var cur_request : http_request option ref = &None;
 
@@ -427,6 +433,11 @@ function init_mod_neko() {
 		headers_not_sent c name;
 		set_header c name val;
 	});
+  def "add_header" (function(name,val) {
+		var c = client();
+		headers_not_sent c name;
+		add_header c name val;
+	});
 	def "get_client_header" (function(name) {
 		match header name request().headers {
 		| None -> neko "null"