Abstract Progressive cavity pump metal to metal has its two elements, rotor and stator, made from a metallic material. It has been demonstrated that this pump can reach an acceptable volumetric efficiency with high viscosity fluids. However, the performance of the pump with two-phase flow has never been investigated. There are not field or experimental tests which provide tools to predict the behavior of the pump in such applications. If progressive cavity pump metal to metal were able to handle high viscosity fluids with gas void fractions, as well as conventional progressive cavity pumps, it could be found a range of application for using this pump in heavy oil production. Its advantages would be valious, since it doesn't have the problems due to the use of elastomer stators. In this research the progressive cavity pump metal to metal performance has been studied. Characteristic curves and instantaneous pressure profiles along the pump with single-phase and two-phase flow have been obtained experimentally. The results show that the internal slip with two-phase flow is a function of gas void fraction, differential pressure and rotational speed. Under some conditions an increase in volumetric efficiency occurs when the gas void fraction is increased. Instantaneous pressure profiles explain the changes of internal sealing lines when gas void fraction changes, also show that longitudinal pressure distribution along the pump have a linear behavior for single-phase and two-phase pumping. The knowledges acquired with this research are useful for understanding the progressive cavity pump metal to metal performance in two-phase pumping applications and also can be used in the future for theorical modeling of the pump.