Purpose: This study aimed to investigate the relationships among job characteristics, knowledge sharing, organizational culture, and organizational commitment in occupational health nurses (OHN) and clinical nurses (CN) to identify factors that might influence organizational commitment. It aimed to contribute to the improvement of knowledge management in health care organizations, including industrial workplaces and hospitals. Methods: A convenience sample of 188 nurses, specifically 100 OHN and 88 CN, was selected. Data were analyzed with descriptive statistics, t-tests, correlation coefficients, and multiple regression analysis. Results: OHNs had a significantly higher education level and current work experience; higher proportion of participants with contract employment status, day work shift, less turnover experience, good lifestyle; and higher scores on organizational culture ($3.3{\pm}0.61$) and organizational commitment ($3.1{\pm}0.60$). Additionally, the correlations among organizational commitment, job characteristics, knowledge sharing, and organizational culture ware higher (r=.38~.57) among OHNs as compared to those among CNs. Further, the organizational commitment of OHNs was significantly influenced by knowledge sharing, organizational culture, working hours, and salary ($R^2=.32$), while that of CNs was influenced by organizational culture and life event stress ($R^2=.11$). Conclusion: There is a need to develop measures to enable nurses to contribute to the improvement of knowledge management in health care organizations as major human resources, by including interventions for the major factors leading to between-group differences in organizational performance.