diff --git a/wp-includes/capabilities.php b/wp-includes/capabilities.php
index b6eff17fa2..80db323819 100644
--- a/wp-includes/capabilities.php
+++ b/wp-includes/capabilities.php
@@ -95,7 +95,7 @@ class WP_Roles {
 	 */
 	function _init () {
 		global $wpdb, $wp_user_roles;
-		$this->role_key = $wpdb->prefix . 'user_roles';
+		$this->role_key = $wpdb->get_blog_prefix() . 'user_roles';
 		if ( ! empty( $wp_user_roles ) ) {
 			$this->roles = $wp_user_roles;
 			$this->use_db = false;
@@ -131,7 +131,7 @@ class WP_Roles {
 		global $wpdb, $wp_user_roles;
 
 		// Duplicated from _init() to avoid an extra function call.
-		$this->role_key = $wpdb->prefix . 'user_roles';
+		$this->role_key = $wpdb->get_blog_prefix() . 'user_roles';
 		$this->roles = get_option( $this->role_key );
 		if ( empty( $this->roles ) )
 			return;
@@ -709,7 +709,7 @@ class WP_User {
 		global $wpdb;
 
 		if ( empty($cap_key) )
-			$this->cap_key = $wpdb->prefix . 'capabilities';
+			$this->cap_key = $wpdb->get_blog_prefix() . 'capabilities';
 		else
 			$this->cap_key = $cap_key;
 
@@ -859,7 +859,7 @@ class WP_User {
 	function update_user_level_from_caps() {
 		global $wpdb;
 		$this->user_level = array_reduce( array_keys( $this->allcaps ), array( $this, 'level_reduction' ), 0 );
-		update_user_meta( $this->ID, $wpdb->prefix . 'user_level', $this->user_level );
+		update_user_meta( $this->ID, $wpdb->get_blog_prefix() . 'user_level', $this->user_level );
 	}
 
 	/**
@@ -901,7 +901,7 @@ class WP_User {
 		global $wpdb;
 		$this->caps = array();
 		delete_user_meta( $this->ID, $this->cap_key );
-		delete_user_meta( $this->ID, $wpdb->prefix . 'user_level' );
+		delete_user_meta( $this->ID, $wpdb->get_blog_prefix() . 'user_level' );
 		$this->get_role_caps();
 	}
 
diff --git a/wp-includes/ms-blogs.php b/wp-includes/ms-blogs.php
index 615535a049..25baf15f68 100644
--- a/wp-includes/ms-blogs.php
+++ b/wp-includes/ms-blogs.php
@@ -498,7 +498,7 @@ function switch_to_blog( $new_blog, $deprecated = null ) {
 	}
 
 	$wpdb->set_blog_id( $new_blog );
-	$GLOBALS['table_prefix'] = $wpdb->prefix;
+	$GLOBALS['table_prefix'] = $wpdb->get_blog_prefix();
 	$prev_blog_id = $GLOBALS['blog_id'];
 	$GLOBALS['blog_id'] = $new_blog;
 
@@ -561,7 +561,7 @@ function restore_current_blog() {
 	$wpdb->set_blog_id( $blog );
 	$prev_blog_id = $GLOBALS['blog_id'];
 	$GLOBALS['blog_id'] = $blog;
-	$GLOBALS['table_prefix'] = $wpdb->prefix;
+	$GLOBALS['table_prefix'] = $wpdb->get_blog_prefix();
 
 	if ( function_exists( 'wp_cache_switch_to_blog' ) ) {
 		wp_cache_switch_to_blog( $blog );
diff --git a/wp-includes/user.php b/wp-includes/user.php
index c9fb60c53a..a88ffcb66b 100644
--- a/wp-includes/user.php
+++ b/wp-includes/user.php
@@ -248,8 +248,9 @@ function get_user_option( $option, $user = 0, $deprecated = '' ) {
 	if ( ! $user = get_userdata( $user ) )
 		return false;
 
-	if ( $user->has_prop( $wpdb->prefix . $option ) ) // Blog specific
-		$result = $user->get( $wpdb->prefix . $option );
+	$prefix = $wpdb->get_blog_prefix();
+	if ( $user->has_prop( $prefix . $option ) ) // Blog specific
+		$result = $user->get( $prefix . $option );
 	elseif ( $user->has_prop( $option ) ) // User specific and cross-blog
 		$result = $user->get( $option );
 	else
@@ -280,7 +281,7 @@ function update_user_option( $user_id, $option_name, $newvalue, $global = false
 	global $wpdb;
 
 	if ( !$global )
-		$option_name = $wpdb->prefix . $option_name;
+		$option_name = $wpdb->get_blog_prefix() . $option_name;
 
 	return update_user_meta( $user_id, $option_name, $newvalue );
 }
@@ -304,7 +305,7 @@ function delete_user_option( $user_id, $option_name, $global = false ) {
 	global $wpdb;
 
 	if ( !$global )
-		$option_name = $wpdb->prefix . $option_name;
+		$option_name = $wpdb->get_blog_prefix() . $option_name;
 	return delete_user_meta( $user_id, $option_name );
 }