Abstract. The aim of the present study was to develop theoretical bio-economic models of Lacaune sheep farms and establish their economic efficiency. Based on three main criteria, 15 options were considered and analyzed. Data were processed using the program EWSH2 as a part of ECOWEIGHT Package for calculating economic weights in livestock. Revenues from sales, variable costs, gross margin and profitability before and after subsidies and per ewe were calculated. It was found that raising sheep of the high productive Lacaune breed could generate profit and provide profitability for the studied models of farms, regardless of the level of selection, type of production system, flock size and even the amount of subsidies. Nucleus farms reported the largest gross margin, followed by the basic and commercial farms. Profitability without subsidies showed the highest values for the nucleus flocks of 1000 ewes – 24.24% when adopting semi-intensive production system and 23.14% for the intensive one. With the addition of subsidies, nucleus and basic farms of 1000 ewes were considered the most profitable with 40% and 37.37%, as for both options the semi-intensive conditions were preferable. A tendency for the values of the studied indicators to grow with the increase in the number of ewes in the flocks was observed, as only for the variable costs it was reversed. Due to the lack of studies on economic efficiency of Lacaune sheep farms in Bulgaria, an additional detailed research, based on real data, is advisable to be conducted.