Integrated farming with fish can play a significant role in increasing the production, income and employment opportunities of rural population. Assam has enormous potential for development of integrated fish farming. The economic viability of integrated fish farming practiced by the farmers of Assam in North- Eastern part of India was evaluated using techno-economic approach. The farmers followed extensive farming practices using low input technology. The objective of this study is to investigate the major integrated fish farming systems and cost and returns of major integrated fish farming system. On the whole, four major integrated fish farming systems were adopted by the sample farmers, e.g. integrated pig -fish farming; integrated poultry -fish farming, integrated horti-fish farming and integrated horti-pig -fish farming. The study revealed that integrated pig-fish farming was the most extensively used farming system and was the most profitable enterprise followed by horti-pig-fish, poultry-fish and horti-fish farming. It was found to be more profitable than unitary system of farming as it ensured a spread of financial risk for its varied and diversified nature of rearing of fish, animals and crops.