Axial flow pumps are widely used in a wide range of applications. Although a different range of axial pump designs can be observed, axial flow pumps are usually designed for high flow rate and low pressure applications. In this study, two different axial flow pump impellers with and without guide vanes are experimentally investigated. The impellers used in the experiments consist of three and four blades. The guide vanes have seven vanes. The experimental set up mainly includes an axial pump, electrical drive motor, storage and calibration tanks and control system. Different impellers are attached to the pump, and the pump characteristics are obtained. As a result of the investigation, it is found that using guide vanes and regaining the tangential velocity energy of the pump improves the total pump efficiency about 3%. Also, the maximum efficiency improvement is obtained at 1000 rpm using guide vanes with a four blade impeller as 65.3%.