A system and method to target advertisements to a user search query using a previously entered user search query as well as the current search query. The previously entered search query can accompanying the current search query in a query referrer, or can be determined separately from the current search query. The relevance of the previous search query is determined with respect to the current search query, and if found relevant a combination of the two query terms is used to find a set of advertising keywords from which candidate advertisements to be targeted and served to the user with search results are found. The process can be extended to additional search queries.