diff --git a/qemu-nbd.c b/qemu-nbd.c
index 0a6091b..c0993b3 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -305,6 +305,7 @@
 int main(int argc, char **argv)
 {
     BlockDriverState *bs;
+    BlockDriver *drv;
     off_t dev_offset = 0;
     uint32_t nbdflags = 0;
     bool disconnect = false;
@@ -312,7 +313,7 @@
     char *device = NULL;
     int port = NBD_DEFAULT_PORT;
     off_t fd_size;
-    const char *sopt = "hVb:o:p:rsnP:c:dvk:e:t";
+    const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:t";
     struct option lopt[] = {
         { "help", 0, NULL, 'h' },
         { "version", 0, NULL, 'V' },
@@ -331,6 +332,7 @@
         { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
 #endif
         { "shared", 1, NULL, 'e' },
+        { "format", 1, NULL, 'f' },
         { "persistent", 0, NULL, 't' },
         { "verbose", 0, NULL, 'v' },
         { NULL, 0, NULL, 0 }
@@ -348,6 +350,7 @@
     bool seen_aio = false;
 #endif
     pthread_t client_thread;
+    const char *fmt = NULL;
 
     /* The client thread uses SIGTERM to interrupt the server.  A signal
      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
@@ -442,6 +445,9 @@
                 errx(EXIT_FAILURE, "Shared device number must be greater than 0\n");
             }
             break;
+        case 'f':
+            fmt = optarg;
+            break;
 	case 't':
 	    persistent = 1;
 	    break;
@@ -543,9 +549,19 @@
     bdrv_init();
     atexit(bdrv_close_all);
 
+    if (fmt) {
+        drv = bdrv_find_format(fmt);
+        if (!drv) {
+            errx(EXIT_FAILURE, "Unknown file format '%s'", fmt);
+        }
+    } else {
+        drv = NULL;
+    }
+
     bs = bdrv_new("hda");
     srcpath = argv[optind];
-    if ((ret = bdrv_open(bs, srcpath, flags, NULL)) < 0) {
+    ret = bdrv_open(bs, srcpath, flags, drv);
+    if (ret < 0) {
         errno = -ret;
         err(EXIT_FAILURE, "Failed to bdrv_open '%s'", argv[optind]);
     }
diff --git a/qemu-nbd.texi b/qemu-nbd.texi
index 3e57200..84d7126 100644
--- a/qemu-nbd.texi
+++ b/qemu-nbd.texi
@@ -41,6 +41,8 @@
   disconnect the specified device
 @item -e, --shared=@var{num}
   device can be shared by @var{num} clients (default @samp{1})
+@item -f, --format=@var{fmt}
+  force block driver for format @var{fmt} instead of auto-detecting
 @item -t, --persistent
   don't exit on the last connection
 @item -v, --verbose