An experimental study was performed to discuss the effects of curvature angles and central disk sizes of 6-curved-blade impellers on the mean drop size in an agitated vessel. A system with 1% oil in water in the presence of a surfactant solution was used. The effects of impeller speed on drop size were also investigated. The laser diffraction technique and RSM method were employed to measure and analyze data, respectively. Decreased curvature angles from 180 degrees to 140 degrees reduced the drop size up to 9%, 10%, and 10% at agitation speeds of 5, 6, and 7 rps, respectively. Moreover, a decrease in central disk size from 3/4D to 1/4D reduced the drop size up to 16%, 18%, and 22% at an agitation speed of 5, 6, and 7 rps, correspondingly. Two mathematical models were suggested and the most significant parameters of each experimental design were identified through the Analysis of Variance.