diff --git a/src/sftp.c b/src/sftp.c
index 6ff2a381..f98601ff 100644
--- a/src/sftp.c
+++ b/src/sftp.c
@@ -1606,6 +1606,7 @@ sftp_file sftp_open(sftp_session sftp, const char *file, int flags,
   sftp_file handle;
   ssh_string filename;
   ssh_buffer buffer;
+  sftp_attributes stat_data;
   uint32_t sftp_flags = 0;
   uint32_t id;
 
@@ -1639,6 +1640,9 @@ sftp_file sftp_open(sftp_session sftp, const char *file, int flags,
     sftp_flags |= SSH_FXF_TRUNC;
   if ((flags & O_EXCL) == O_EXCL)
     sftp_flags |= SSH_FXF_EXCL;
+  if ((flags & O_APPEND) == O_APPEND) {
+      sftp_flags |= SSH_FXF_APPEND;
+  }
   SSH_LOG(SSH_LOG_PACKET,"Opening file %s with sftp flags %x",file,sftp_flags);
   id = sftp_get_new_id(sftp);
   if (ssh_buffer_add_u32(buffer, htonl(id)) < 0 ||
@@ -1686,6 +1690,22 @@ sftp_file sftp_open(sftp_session sftp, const char *file, int flags,
     case SSH_FXP_HANDLE:
       handle = parse_handle_msg(msg);
       sftp_message_free(msg);
+      if ((flags & O_APPEND) == O_APPEND) {
+        stat_data = sftp_stat(sftp, file);
+        if (stat_data == NULL) {
+            sftp_close(handle);
+            return NULL;
+        }
+        if ((stat_data->flags & SSH_FILEXFER_ATTR_SIZE) != SSH_FILEXFER_ATTR_SIZE) {
+          ssh_set_error(sftp->session,
+                        SSH_FATAL,
+                        "Cannot open in append mode. Unknown file size.");
+          sftp_close(handle);
+          return NULL;
+        }
+
+        handle->offset = stat_data->size;
+      }
       return handle;
     default:
       ssh_set_error(sftp->session, SSH_FATAL,