Gas holdup and bubble size are two of the most important factors characterizing hydrodynamics in a flotation cell. Gas holdup produced in a stirred vessel is a basic measure of the effectiveness of the contacting and mixing. Although no universally applicable model to predict gas holdup is yet available, chemical engineering literature suggests a number of empirical correlations. All previous investigators measured gas holdup; some attempted to measure interfacial area and bubble size. Therefore, in this study the main attention was given to the effects of operating variables on overall gas holdup in a flotation cell.