Tomato has been an important vegetable crop with high potential production for import-substitution and export purposes since the Sixth National Economics and Social Development Plan (1987-1991). But, tomato plantation faces serious problems of insect damage and several diseases, especially tomato root and stem rot caused by Selerotium rolfsii Sacc. The main objectives of this research are to analyze the cost and revenue of tomato production and to study the possibility of production Trichoderma powder in commerce to be used to control such tomato root and stem rot disease. The results of the study showed that average production cost and revenue of tomato was estimated at about 6,518.89 and 8,416.03 baht per rai, respectively. The possibility of production Trichoderma powder has some potential by comparing economic loss of the disease with the expenditure of using the powder and its efficiency to control the disease

and comparing average production cost, output quantity and net profit in case of using with without using the powder. However, such possibility potential will be low or high depends upon several factors, such as tomatos sales price, Trichoderma powders potential demand, the powders efficiency to control Sclerotium Root and Stem Rot of tomato and to control diseases of other crops and promotional sales cost of the powder.