Diesel engines are the prime movers for heavy duty vehicles used in the transportation and agricultural sectors. Diesel engines meet their energy requirement from stored fuels, i.e. petroleum products. The twin problems of both depletion of scarce resources and atmospheric pollution caused by vehicles run on petro-products are enticing researchers to find a viable and immediate alternative to fossil fuels. The physical and combustion properties of vegetable oils are close to those of petro-Diesel fuel, and in this context, vegetable oils can stand as an immediate candidate to substitute for stored fuels. Vegetable oils are produced from processing the seeds of various plants and, thus, are renewable in nature. Sustainable development of a country depends on the extent that it is managing and generating its own resources. This also helps in conservation of depleting non-renewable petro-products. However, due to inherent high viscosity and low volatility, vegetable oils would pose problems, such as fuel flow and poor atomization, and constrain their direct use in engines without any modifications. In the present investigation, the effect of supercharging is studied on the performance of a direct injection Diesel engine with the use of untreated cotton seed oil under varying injection pressures (IP's). The performance of the engine is evaluated in terms of brake specific fuel consumption (BSFC), exhaust gas temperature and smoke density. It is observed that when cotton seed oil is used as a fuel, there is a reduction in BSFC of about 15% when the engine is run at the recommended IP and supercharging pressure of 0.4 bar (g) in comparison with the engine operation run under naturally operated conditions. The investigation revealed that cotton seed oil, in general vegetable oils, can best be utilized if supercharging is employed at the recommended IP of the engine.