Abstract: Population dynamics of male and female T. ilisha in Bangladesh water were studied using the length frequency based analysis of FiSAT software to evaluate the growth parameters, mortality rates, exploitation levels, Maximum Sustainable Yield (MSY) and the corresponding fishing mortality. The study reveals that the fishes are harvested at a level than the optimum fishing mortality. The fishing pressure should be reduced to about 1.08/year, i.e. 9% reduction from the present level of mortality per year for obtaining MSY, 235,130 tones.