To analyse the effect of both professional and care unit commitments on attitudes towards interprofessional collaboration between nurses and physicians.The effects of both professional and care unit commitment on inter-professional collaboration have not been taken into account together, and previous research has analysed only one profession at a time, neglecting the nurse-physician comparison.A cross-sectional survey of 138 physicians and 359 nurses was used.For physicians, professional commitment decreased attitudes towards interprofessional collaboration whereas care unit commitment had a positive influence. Conversely, for nurses, the professional commitment had a significant positive effect on attitudes towards interprofessional collaboration whereas care unit commitment had no significant effect.Intergroup relations affect the extent to which nurses and physicians are inclined to engage in interprofessional collaboration. Professional and care unit commitments had different effects on attitude toward the inter-professional collaboration of nurses and physicians.Inter-professional collaboration is affected by the relationship between physicians and nurse at the professional group level. Managers who want to change and improve inter-professional collaboration should pay close attention to the interplay between changes they are introducing and well-established identities and practices between professionals.