The purpose of the investigation was to determine the influence of certain factors on the velocity of saponification of fats and oils by potassium hydroxide. The idea of measuring the velocity of a reaction was first suggested by K. F. Wenzel in 1777. Wenzel defined the velocity of a reaction as the ratio, ( x/d±\ of the amount of substance changed to the time in which it is changed. This definition is still accepted. The factors influencing the velocity of a reaction are, in general, the concentration of the reacting substances, the temperature, the pressure, the solvent, catalytic agents, and the homogenity or heterogenity of the system. Of these, the factors that need to be considered in this work are: (a) Concentration of reacting substances (b) Temperature (c) Solvent (d) Catalytic agents. The influence of concentration on the velocity of reaction is best stated by the law of mass action; the velocity