The usage of neat cashew nut shell oil (CSNO) as a fuel in direct injection diesel engine suffers from the problems of incomplete combustion and low brake thermal efficiency due to high viscosity. To overcome this problem, the CSNO was blended with camphor oil (CMPRO) which is less viscous and burns readily, in various proportions by volume. These blends were tested in a single cylinder 1500 rpm, 5.2 kW, direct injection diesel engine fitted with eddy current dynamometer. The performance, emission and combustion characteristics were studied at various loads on the engine at a constant speed of 1500 rpm and compared with neat CSNO and diesel fuel operations. Among the blends 30% camphor oil blend with CSNO (CMPRO 30), shows good performance on par with diesel fuel operation with respect to brake thermal efficiency and heat release rate at full load. The brake thermal efficiency of CMPRO 30 is 29.1% compared to base diesel engine brake thermal efficiency of 30.14%. The CMPRO 30 emits 1040 ppm of NO, while diesel emits 1068 ppm. The neat CSNO emits 983 ppm of NO. The smoke emissions are 4.22, 3.91, and 3.64 Bosch Smoke Unit for CSNO, CMPRO 30 and diesel, respectively. (C) 2012 Elsevier Ltd. All rights reserved.