Diesel engines have high efficiency, reliability and durability together with their low operating cost. These important features make them to be widely used in the transportation, automotive, agricultural application and industrial sector. These wide fields of usage lead to the increasing requirements of petroleum derived fuel and going for depletion of petroleum fuel shortly. Hence, it is essential to go for an alternate fuel to diesel and effective control of the various pollutants emitted by the diesel engines. The major pollutants emitted by the diesel engines are unburned hydrocarbon (HC), carbon monoxide (CO), oxides of nitrogen (NOx), particulate matter (PM), sulphur oxides (SOx) and lead. These pollutants can cause health problems to human beings and will have an impact on the environment such as climate change, global warming, acid rain, ozone depletion and photo chemical smog. Therefore, the researchers are intended to find out the viable substitute alternate fuel for diesel and control of pollutants from compression ignition (CI) engines. The biodiesel can be used as alternate for diesel, which is a non-fossil fuel, easily available and cheaper. The main drawbacks of biodiesel operated CI engine are reduced performance and increased NOx emission. In order to improve the performance and to reduce exhaust emissions, suitable methods have to be incorporated. Hence, in the present review a detailed study has been carried out with the operating parameters and catalytic converter in biodiesel operated engine, so that its performance can be improved and exhaust emissions were reduced.