This study presents the impact of biodiesel blends produced by sunflower oil residues and industrial palm oil residues on the performance parameters of a single-cylinder diesel engine. For the combustion performance analysis, the brake thermal efficiency and the brake specific fuel consumption parameters of the engine are investigated. The emissions study has focused on the measurement of CO2, NOx, CO, opacity, and HC of exhaust gases. The experiments have been performed for a loading condition of 20%, 40%, 60%, 80%, and 100%. The test fuels used have been commercial diesel (D100) and biodiesel blends (PB5, PB5SB2, and PB5SB4). The biodiesel blends PB5SB2 and PB5SB4 cause a reduction in the maximum pressure values and in the rate of heat release by 5.85% and 8.53%. Experimental results show that the content of the residual sunflower oil produces an increase in engine BSFC. This effect causes a decrease in engine BTE. However, the decrease caused has not affected the engine performance significantly. The biodiesel blends PB5SB2 and PB5SB4 cause a decrease in the emissions of HC, CO2, and CO. PB5SB2, and PB5SB4 fuels reduce the aforementioned emissions by 14%, 16%, and 22% compared to commercial diesel. The content of sunflower oil residues allows the reduction in smoke opacity. However, nitrogen oxide emissions have increased. The results obtained show that biodiesel produced from palm and sunflower oil residues provides a considerable reduction in large part of the emissions produced by a diesel engine without significantly affecting engine efficiency.