Hot temperatures increase the risk of dehydration. Fluid with certain osmolarity and contain of electrolytes can prevent dehydration. Banana isotonic drinks (BID) was developed for rehydration. This study aims to determine the difference effect of BID and plain water (PW) of body hydration. Experimental research using a cross over design involved 16 subjects and divided into two groups. After undergoing two days of quarantine, each subject was administrated with 500 ml of fluid. Wash-out period between treatments was 7 days. Indicator of hydration of hemoglobin, HCT, and urine volume are assessed before and after intervention. The result showed that indicator of hydration differed significantly after receiving the intervention (P <0.05) although there was no difference between groups (P >0.05). However, urine volume formation was higher on the PW than BID group. BID is able to improve the hydration of the body through the mechanism of maintaining body volume and slowing down the urine formation.