Biodiesel as alternative fuel has been widely studied due to its merits such as lower sulfur, lower aromatic hydrocarbon and higher oxygen content. Rice bran oil is extracted from the germ and inner husk of the rice and is not a common source o f edible oil. The aim of this paper is to study the effect of injection pressure on the emission characteristics of a single cylinder diesel engine using diesel and the blends of diesel and rice bran biodiesel, B10 (90% diesel + 10% rice bran biodiesel), B20 (80% diesel + 20% rice bran biodiesel) and B30 (70% diesel + 30% rice bran biodiesel). The injection pressure is varied from 180 bar to 240 bar with an interval of 20 bar. The exhaust gas emissions such as carbon monoxide (CO), hydrocarbon (HC), oxides of nitrogen (NO x ), carbon dioxide (CO 2 ) and smoke opacity are measured at the rated power and speed at different injection pressures. It is observed that the minimum CO, HC and smoke emissions are recorded at 220 bar. The NO x, emissions are increased and CO 2 emissions decreased with the injection pressure. Th e optimum injection pressure is 220 bar and the blend is B20 with respect to emissions.