Some aspects of the reproductive biology of Hilsa Shad, Tenualosa ilisha from the Persian Gulf and rivers of Khouzestan Province of Iran were analyzed. A total of 485 fish were sampled by gillnet from landing center of Arvand (AR) and Bahmanshir (BR) rivers during period of April 2010 to September 2010. Reproductive characteristic of T.ilisha showed that sex ratio is M: F=1:2, in PG, AR and BR. This means that females predominate than males. Monthly variations in Gonadosomatic index (GSI) of both sexes were quite apparent. In PG, maximum values were recorded in April for male and female. In AR and BR, maximum values were recorded in June and May for male and female, respectively. Changes in GSI indices are considered as a proof that maturation season in AR and BR is started from March and spawning is started from April to July in AR and BR is started from March to August. The Length - Weight relationship was measured for PG as W= 1.459L2.687, AR and BR as W=2.189L3.166 and W=1.840L2.937, respectively.