Micro. -reaction/reactor technology has been used to intensify several chemical processes involving gas-liquid and liquid-liquid reactions. However, potential of intensifying gas-liquid-liquid reactions still remains unexplored. In the present work, we report experimental investigations of gas-liquid-liquid three-phase flows in microchannels. High-speed imaging experiments were performed to identify and to map flow regimes; to understand the effect of flow rates of continuous (kerosene) and dispersed phases (air and water) on the flow regimes, formation mechanisms of air bubbles/slugs and water drops/slugs and also to measure the slug lengths. In particular, the effects of different gas and liquid distributors and addition of surfactant were investigated to understand controlled generation of bubbles and drops and formation of different flow regimes in microchannels. The results presented in this manuscript will be important to device microreactor systems for catalytic reactions involving gas-liquid-liquid flows. © 2012 Elsevier B.V.