This document summarizes an experimental study on the performance and emission characteristics of a diesel engine fueled with cotton seed oil methyl ester (CSOME) biodiesel. Experiments were conducted on a single cylinder diesel engine operated on diesel, CSOME, and their blends. The experiments revealed that optimized operating parameters for CSOME included a start of injection of 190° bTDC, injection opening pressure of 230 bar, compression ratio of 17.5, and a 4-hole nozzle with diameter of 0.3 mm. These optimized parameters resulted in thermal efficiency that was approximately 17.7% higher than the baseline parameters at full load. Emissions of hydrocarbons and carbon monoxide decreased with CSOME