This research aims to determine the effect of work ethos, work discipline and organizational commitment on employee performance at PERUMDAM Tirta Wijaya Cilacap. The population of this research is all employees of PERUMDAM Tirta Wijaya Cilacap, was 198 employees and the sample of this research was 126 employees of PERUMDAM Tirta Wijaya Cilacap using purposive sampling techniques and data obtained from respondents with research instruments using questionnaires. The method used in this research is multiple regression analysis. The results revealed that the work ethos, work discipline and organizational commitment variables had a significant effect on employee performance. The results of the partial analysis test partially show that work ethos partially had a significant effect on employee performance, work discipline partially had a significant effect on employee performance, organizational commitment partially does not have a significant effect on employee performance