ABSTRACTIn this study, yellow oleander biodiesel was produced using a calcium oxide catalyst. The fuel properties of the yellow oleander biodiesel were in the range of ASTM standards. Effects of the yellow oleander biodiesel and its blends (B10, B20, B30, B40 and B100) were investigated at five different loads (0, 25, 50, 75 and 100%) in a single-cylinder CI engine. Comprehensive combustion analysis showed that the starts of injection timings were inadvertently advanced from the system response. The combustion of yellow oleander biodiesel and its blends generally resulted in a shorter ignition delay period for all loads due to earlier combustion timing. The performance, combustion and emission characteristics of yellow oleander biodiesel and its blends were studied. Variation in the engine emissions were recorded using an AVL DIGAS 444 analyzer. The CO and HC emissions were less for biodiesel test blends (except B100) but NOx emissions increased with closer engine performance when compared to diesel.