Washing hands is a process that mechanically removes dirt and debris from the skin of the hands by using ordinary soap and water to prevent nosocomial infections. The purpose of this study was to determine the relationship between nurses' knowledge and attitudes about proper handwashing in private hospitals in Indonesia. This research method is quantitative correlational with a population of 51 people and total sampling techniques in all inpatient rooms. The instrument used in the form of a questionnaire that had been tested for validity and reliability with Cronbach's alpha value on the knowledge variable was 0.67 and the attitude variable was 0.76. The results of this study reveal that there is a significant relationship between nurses 'knowledge and nurses' attitudes with a value of p = 0.00. The next recommendation for researchers is to continue research on nurses' adherence to correct handwashing behavior at five moments.