Background. A nursing work method is the base for the organization and implementation of nursing care to patients based on nurses’ skills. Nurses’ work methods are consensually organized into two groups: task-oriented work methods (functional method) and client-centered work methods (teamwork method, individual work method, and work method per reference nurse). As for the impact of the work method on clients, we highlight the interference in the quality of care provided and, regarding nurses, the impact on workload and job satisfaction. Therefore, the existence of tools that allow identifying the organizational methodologies of nursing care is relevant. Aim. The aim of the study is to test the validity and reliability of the nurses work methods assessment scale (NWMAS). Methods. The methodological study followed the recommendations of the EQUATOR network. The NWMAS was previously developed as a self-completion questionnaire. To determine construct validity, exploratory and confirmatory factor analyses were performed. Results. 325 participants were enrolled in this study. In exploratory factor analysis, the 25 items comprising NWMAS were distributed in five dimensions, contemplating the work methods. Cronbach’s alpha of the total scale was 0.846. The confirmatory factor analysis revealed a good fit. Conclusion. The NWMAS is a valid and reliable tool. Implications for Nursing Practice. The NWMAS identifies the work methods adopted by nurses in hospital settings, is a valuable tool for nursing management, and contributes to the definition of strategies that promote the quality of nursing care and the safety of patients.