Objective To increase fluid intake in mildly disabled institutionalized elders and to reduce the occurrence of problems caused by inadequate fluid intake. Methods A total of 99 mildly disabled institutionalized elders were randomized into a control group of 50 and an intervention group of 49, receiving either routine fluid intake care or intervention aiming to increase fluid intake by employing the concept of supporting self-care. Daily water intake, plasma osmotic pressure, urinary tract infection and constipation were evaluated before and at 3, 6 months after the intervention.Results The daily water intake at 3 and 6 months after the intervention were significantly higher, whereas the value of plasma osmotic pressure at 6 months after the intervention were significantly lower in the intervention group than the control group （P＜0.05,P＜0.01）.There were no significant differences in the incidence of urinary tract infection and constipation between the two groups （P＞0.05 for both）.Conclusion The implementation of water intake regimen based on the concept of supporting self-care for the mildly disabled elderly in elder-care institutions can increase daily water intake and improve parameters of the body.