The purpose of this study was to compare the effects of underwater treadmill gait training (UTGT) and overground treadmill gait training (OTGT) on the gait, balance ability and pulmonary function of stroke patients. Twenty subjects were recruited for this study. The subjects were randomly assigned to two groups: UTGT (n1=10) and OTGT (n2=10). The 10 m walk test (10 MWT), Berg Balance Scale, Timed Up and Go (TUG) test, center of pressure, pulmonary function of forced vital capacity (FVC), forced expiratory volume after 1 sec (FEV1) and FEV1/FVC were measured before and after 4 weeks of training. Both groups undertook the gait training for 30 min a day, 3 times a week, for 4 weeks, and rating of perceived exertion of the groups were measured and compared. All the studied variables were significantly improved in both groups (p<.05) at the end of the study, except in the FEV1 of OTGT (p>.05). There was significant between-group difference in all of the variables, except in the 10 MWT (p>.05). These findings suggest that UTGT is more effective than OTGT in improving the balance and pulmonary functions of stroke patients.