$term_show_block = 15;
if (arg(0) == 'node' && arg(1) && is_numeric(arg(1))) {
  $node_obj = node_load(arg(1));
   $terms = taxonomy_node_get_terms($node);
    foreach($terms as $term) {
      if (($term->tid == $term_show_block) ) {
         return TRUE;
      }
    }
}