A modified stirred-cell type contactor has been designed and tested for its use in experimental investigations of mass transfer and chemical reaction in liquid-liquid systems. Its design overcomes the shortcomings of previously proposed contactors. It is easy to operate and has the ability to investigate the. effect of a wide range of operating conditions. The mixing performance of the contactor was tested using a dye injection and. a tracer technique. Experiments to evaluate mass-transfer coefficients across a Liquid-liquid interface have been conducted to determine its effectiveness, The results verified that the contactor could be successfully employed as a useful experimental research apparatus.