ABSTRACTDrought stress is one of the major limiting factors for plant growth and production in the tropic area because it can reduce crop yield sup to average 50%. Therefore, the mechanism of drought tolerance is important to be studied. Drought stress can cause a decrease in water potential, osmotic potential, and potential pressure, which leads to increased accumulation of proline. Proline accumulation can be cause dactivists proline synthesis from glutamate, proline oxidation decreased speed, low protein synthesis and decreased delivery proline into the phloem. Proline synthesis of glutamate stimulated by abscisic acid (ABA). While theoxidation of proline and protein synthesis of prolineis not influenced by the ABA. Proline accumulationon the state of water stress serves as osmoregulation, protective enzymes and membrane structure, keeping water in the cells by binding water from the soil due to increased osmotic potential becomes more negative.Keywords : osmotic regulation, drought stress, proline, glutamate, abscisic acid