Mixing of fluids is a central component to innumerable operations in chemical processing on the plant floor and also in many laboratory operations. Most mixing applications simply require the efficient blending of fluids present in a single phase, such as the mixing of the individual components of a liquid. For these applications, magnetic stirrers often prov ide a convenient and efficient blending without creating ambient air entertainment into the liquid. This is especially true of fluid mixing operations done in the laboratory. There are many other applications, however, in which the entertainment of a vapor phase with a liquid is specifically desired. Examples of these applications include mixing in two-phase reaction vessels and in apparatus to measure vapor-liquid equilibrium. These mixing operations are difficult to accommodate with magnetic stirrers because the vast majority of such stirrers are designed not to entrain vapor. In this brief paper, we present a novel design of a mixing rotor that efficiently mixes the liquid phase and also achieves entrainment of vapor in the liquid.