An operational model was derived which can be used to analyze the performance of Bangladesh riverine fisheriesunder different simulated alternatives of technical, economic and biological conditions. Functions and parameters of a base model were estimated by deriving 2 submodels: 1) bioeconomic production and 2) the market, using regression techniques. Results of the base model suggest that the riverine fisheries of Bangladesh are capable, under optimal conditions, of generating a total net benefit of BDT (Bangladesh Taka) 1,383 million per annum (US$1 = BDT32), of which 96% would accrue as producer surplus. Simulation of cost and demand changes reveal that the effect of changes in the cost condition of harvest will in general be related negatively to the intensity oftotal effort use, total landings, benefits and costs while the effects of changes in the aggregate demand on total effort, total costs, landings, prices and net benefits will be positive. Intervention into the fisheries through control on effort intensity would produce substantial net benefits from the fisheries.