Aquaculture has been identified by the Government of Trinidad and Tobago as a competitive industry with the potential of reducing high fish imports. The purpose of this study was to provide an economic analysis of the factors affecting overall profitability of tilapia production in Trinidad. Thirty farmers selected for the survey were actively involved in a semi intensive or extensive grow out systems production. Data collection was via a structured questionnaire and semi structured interviews. An econometric regression model for the study tested the effects of output (0), selling price (SP), cost of feed (FD), fingerlings (FNG), labour (LAB), and operational costs (OC), with dummy variables tank culture (CT), sex culture (SC), and production system (PS) on the profitability of tilapia production. The Ordinary Least Squares (OLS) method was used and included appropriate tests for multicollinearity. Furthermore, the model provided relevant OLS information on the R-Squared and Durbin-Watson statistics for profitability. The OLS best fit equation derived for PROFIT = -13759.950 + 12.0480 + 1492.922SP + 0.144FD - 2.621 FNG -1.338LAB + 1.1200C - 4147.623CT - 1552.083SC - 4191.806PS Output and labour cost (P< 0.0001) followed by operational costs (P < 0.01), selling price and cost of fingerlings (P< 0.05) were the main determinants affecting the profitability of these farmers. Two models comparing medium and large farm sizes showed that large farm sizes had higher Net Present Value (NPV's) and Internal Rates of Return (IRR). For farmers to improve profitability, focus should be placed on increasing output and controlling labour costs which are high in comparison to the low levels of output produced under these systems of management. In order for output to increase there will also be a need for better farm management, and better training in aquaculture farming techniques.