This paper presents a detailed investigation of the effect of swirl atomizer geometry on the droplet size distribution. This includes the investigation of the effect of pressure drop across the atomizer, length/diameter ratio of the swirl chamber, length/diameter ratio of the orifice, and the orifice, diameter upon the droplet size distribution. The slide sampling technique is used for the determination of the drop-let size. A new analytical method for the Tanasawa-Tesima distribution equation is proposed. The Weibull distribution function is also tested for evaluation of the measured distribution. The dependences of the shape parameters, for the two distributions on the atomizer geometry and working pressure are summerized in useful empirical equations. These correlation equations can be used for the prediction of the atomizer geometry and the operating conditions which satisfy a specified liquid atomization quality.