diff --git a/src/fix_print.cpp b/src/fix_print.cpp
index 198b1fd8be..6181600acb 100644
--- a/src/fix_print.cpp
+++ b/src/fix_print.cpp
@@ -46,10 +46,11 @@ FixPrint::FixPrint(LAMMPS *lmp, int narg, char **arg) :
 
   int iarg = 5;
   while (iarg < narg) {
-    if (strcmp(arg[iarg],"file") == 0) {
+    if (strcmp(arg[iarg],"file") == 0 || strcmp(arg[iarg],"append") == 0) {
       if (iarg+2 > narg) error->all("Illegal fix print command");
       if (me == 0) {
-	fp = fopen(arg[iarg+1],"w");
+	if (strcmp(arg[iarg],"file") == 0) fp = fopen(arg[iarg+1],"w");
+	else fp = fopen(arg[iarg+1],"a");
 	if (fp == NULL) {
 	  char str[128];
 	  sprintf(str,"Cannot open fix print file %s",arg[iarg+1]);