This study aimed to analyze the economic viability of tilapia farming (Oreochromis niloticus) using a small-scale recirculating water system in the municipality of Parnaiba-PI, Brazil. We verified the marketing data regarding the economic viability of two production cycles, using three 2.5 x 5.7 x 0.7 meter tankss, with a final weight of 500 grams. With the data obtained, the annual production of 660 kg after two cycles of fattening of 165 days were estimated. Indicators such as gross revenue, operating income, gross margin, profitability index, leveling point, net present value, benefit cost ratio, payback, internal rate of return and sensitivity analysis were analyzed. The implementation cost was of R$ 9,370.94. Given that the return investment will occur in the sixth month of the fifth year, the Net Present Value (NPV) is of R$ 2.759.55, the leveling point is of 38.20% and the Internal Rate of Return (IRR) will be of 19.40%. With this, the project can be considered economically viable, provided it is not the only source of family income, since it is able to generate a monthly income equivalent to R$ 226.91.