Two-phase flow is an excellent alternative to the conventional single-phase system in transporting large amount of thermal energy at a uniform temperature regardless of variations in the heat loads. In addition, two-phase flows exist in a wide range of applications and enabling technologies in space. These include material processing and ceramics at ultra high temperatures, bioreactors and life-support systems, storage and transport of cryogenics, tank filling and fluid management, and in the design of many cold plate assemblies where heating (or cooling) takes place at the instrument/utility interface. Reliable design of such systems and many others require a thorough understanding of the mechanics of the two-phase flow under microgravity conditions. Of most interest are the phase distribution in a conduit (the flow patterns/regimes), the pressure drop, and the heat-transfer rates at different liquid and gas flow rates. Recent progress in the study of gas-liquid flows at microgravity conditions will be reviewed and discussed in this paper with emphasis on the heat-transfer aspects of the flow.