There is an increasing number of community-based question and answer (cQA) service on the Web. Many tasks in cQA services involve in determining similarity between questions. However, finding similar questions is not trivial. In this paper we propose a new method based on a query expansion technique to tackle the similar question matching problem. We employ the information provided by the corresponding answer and question & answer pairs from cQA services to determine the similarity between questions. We empirically show that with this method it is possible to find semantically similar questions even though they may not share any actual terms in common.