Saitō Yoshitatsu was a Japanese samurai during the Sengoku period.Yoshiatsu was the son of Saitō Dōsan. In 1556, Dōsan was killed in battle against forces led by Yoshitatsu.Yoshitatsu then died of leprosy.The son of Yoshitatsu, Saitō Tatsuoki, was defeated by Oda Nobunaga in 1564; and the clan disappeared.