diff --git a/pam/pam_fprintd.c b/pam/pam_fprintd.c
index 1aeb415..8449875 100644
--- a/pam/pam_fprintd.c
+++ b/pam/pam_fprintd.c
@@ -613,7 +613,7 @@ PAM_EXTERN int pam_sm_authenticate(pam_handle_t *pamh, int flags, int argc,
 				   const char **argv)
 {
 	const char *username;
-	unsigned i;
+	int i;
 	int r;
 
 	bindtextdomain (GETTEXT_PACKAGE, LOCALEDIR);
diff --git a/src/device.c b/src/device.c
index 3c9b467..29dde1c 100644
--- a/src/device.c
+++ b/src/device.c
@@ -1030,7 +1030,7 @@ static gboolean fprint_device_verify_start (FprintDBusDevice *dbus_dev,
 	g_autoptr(FpPrint) print = NULL;
 	g_autoptr(SessionData) session = NULL;
 	g_autoptr(GError) error = NULL;
-	guint finger_num = finger_name_to_num (finger_name);
+	int finger_num = finger_name_to_num (finger_name);
 
 	if (!_fprint_device_check_claimed (rdev, invocation, STATE_CLAIMED, &error)) {
 		g_dbus_method_invocation_return_gerror (invocation, error);