Saitama 3rd district (埼玉県第3区 Saitama-ken dai-sanku or simply 埼玉3区 Saitama 3-ku) is a constituency of the House of Representatives in the Diet of Japan. It is located in Southeastern Saitama and consists of the cities of Sōka and Koshigaya. As of 2012, 460,884 eligible voters were registered in the district. Before the electoral reform of 1994, Sōka was part of the where three Representatives had been elected by single non-transferable vote, and Koshigaya part of (four Representatives).