Build an EntityFieldQuery that selects referenced entities
You can use target_id instead of value to retrieve entities based on the ID of referenced entities:

$query = new EntityFieldQuery();
$query-&gt;entityCondition('entity_type', &lt;type-of-the-entity&gt;);
$query-&gt;fieldCondition('&lt;name-of-the-field-referring-the-other-entity&gt;', 'target_id', &lt;id-of-the-referenced-entity&gt;, '=');
$results = $query-&gt;execute();