The aim of this experimental work, is to compare the performance and emission characteristics of emulsified fuel in the conventional engine. A single cylinder direct injection diesel engine has been used for this investigation. Diesel water emulsion has been chosen as the test fuel and diesel has been considered as the reference fuel. As the diesel and water are immiscible, surfactants have been used to form a homogeneous mixture called emulsion. The surfactants used are span 80 and tween 80. Water has been mixed for the proportions of 5%, 10%, and 15% by volume with diesel. For all the emulsions, 1% of surfactant has been used. It was found that the brake thermal efficiency was almost close to diesel and simultaneous reduction of smoke and oxides of nitrogen (NOx) emission. Suggested scope for this experimental investigation might be an endurance test and fuel additives to increase the calorific value. © 2015 Journal of Chemical and Pharmaceutical Sciences.