A fuel derived from crude oil is the case of crucial in various countries, one of which Indonesia. The increasing demand for fuel the increase varies inversely with the availability of energy sources. Various efforts of the fuel as well as replacing fossil fuels with fuel that is renewable is derived from vegetable oil. In this research is done mixing between Castor oil and Nyamplung oil The mixing of both are made in temperatures 80°C for 30 minutes and variations of time mixing 30, 60, 90 minutes to sample a mixture of 50 % : 50 %, to determine the influence of a mixture of Castor oil and Nyamplung oil to the character of a mixture of it as fuel by comparison. Based on the results of research of the physical properties and chemical properties obtained the results of the density in a mixture of Castor oil and Nyamplung oil on the range 915,524 kg/m ³ to 932, 94 kg/m ³. The viscosity of a mixture of Castor and Nyamplung oil on the range 69.905 cSt to 203,951 cSt. The heat a mixture of Castor oil and Nyamplung oil on the range 8880, 293 kal/g to 9116, 142 kal/g. The flash point a mixture of Castor oil and Nyamplung oil on the range from 228, 5°C to 266, 5°C. More quantity of oil on a mixture of Castor oil and Nyamplung oil, then the value of the density, viscosity, and the flash point is increasing, otherwise the value of the heat getting down, fatty acids that dominate the Castor oil is linoleic acid, 59 % and Nyamplung oil is the acid oleat, 59 %.