This paper aimed to investigate the fishery and biological characteristics of anchovy Kilka in Iranian waters of the Caspian Sea from 2005-2007, including length and age structure ,Von Bertalanffy growth parameters, length and age at first capture, condition factor, sex ratio, natural and fishing mortality. The examination of catch data approved that Kilka population in the Caspian Sea have been declined a few years ago following entrance jellyfish Ctenophora Mnemiopsis leidyi. The greatest destruction of anchovy kilka catch was occurred while the catch of anchovy from 4250 tonnes in 2005 reached to 924 tonnes in 2007. The results showed that K value and L_∞ calculated 0.375/year, 131.7mm, respectively. The instantaneous coefficient of natural mortality was estimated 0.49/year.The instantaneous coefficient of fishing mortality and total mortality was 0.51 /year and 1/year, respectively. The Exploitation rate was calculated as 0.51. The length and age ranges restricted comparison to last decade and sharply decreased recruitment. In the past few years, the main reasons of disintegrates among anchovy Kilka stocks in the Caspian Sea were synchronized overfishing competitive anchovy Kilka with M. leidyi.