diff --git a/source3/configure.in b/source3/configure.in
index 408340d..f8b5534 100644
--- a/source3/configure.in
+++ b/source3/configure.in
@@ -4241,6 +4241,25 @@ AC_ARG_WITH(pam_smbpass,
 )
 
 
+#################################################
+# Which passdb backend to use as default (tdbsam or smbpasswd)
+AC_MSG_CHECKING(whether to use tdbsam or smbpasswd as default passdb backend)
+AC_ARG_WITH(default-passdb-backend,
+[AS_HELP_STRING([--with-default-passdb-backend], [Use tdbsam or smbpasswd as default passdb backend (default=tdbsam)])],
+[ case "$withval" in
+  smbpasswd)
+    AC_DEFINE(DEFAULT_PASSDB_BACKEND, "smbpasswd", [Use smbpasswd as default passdb backend])
+    AC_MSG_RESULT(smbpasswd)
+    ;;
+  *)
+    AC_DEFINE(DEFAULT_PASSDB_BACKEND, "tdbsam", [Use tdbsam as default passdb backend])
+    AC_MSG_RESULT(tdbsam)
+    ;;
+  esac ],
+  AC_DEFINE(DEFAULT_PASSDB_BACKEND, "tdbsam", [Use tdbsam as default passdb backend])
+  AC_MSG_RESULT(tdbsam)
+)
+
 ##
 ## moved after the check for -lcrypt in order to
 ## ensure that the necessary libraries are included
diff --git a/source3/param/loadparm.c b/source3/param/loadparm.c
index 553938f..3296cec 100644
--- a/source3/param/loadparm.c
+++ b/source3/param/loadparm.c
@@ -4982,7 +4982,9 @@ static void init_globals(bool first_time_only)
 	   a large number of sites (tridge) */
 	Globals.bHostnameLookups = False;
 
-	string_set(&Globals.szPassdbBackend, "tdbsam");
+	/* default to tdbsam as passdb backend; use the obsoleted smbpassdb on
+	   request; cf. the --with-default-passdb-backend configure option */
+	string_set(&Globals.szPassdbBackend, DEFAULT_PASSDB_BACKEND);
 	string_set(&Globals.szLdapSuffix, "");
 	string_set(&Globals.szLdapMachineSuffix, "");
 	string_set(&Globals.szLdapUserSuffix, "");