OBJECTIVE To examine how difficult decisions to hospitalize nursing home patients are considered by the physicians and to what patient characteristics this is related. METHODS Prospective and descriptive. METHODS Analysis of registration data about 387 decisions to hospitalize nursing home patients collected among nursing home physicians in 30 nursing homes. RESULTS The degree of difficulty of hospitalisation was associated primarily with poor physical condition and much less with the mental condition. It was not related to patient age (apart from physical condition and the reason for hospitalisation). Referrals were difficult for e.g. infections and respiratory tract disorders, which may be further complicated by the short time available for the decision making because of the life threatening nature of the disorders. With malignancies, feeding, urogenital and skin disorders, decisions to hospitalize also proved difficult to make. These disorders usually allowed more time for consultation. CONCLUSIONS About half the decisions to hospitalize were considered hard to make. Only when there is better insight into the effects of hospitalisation on patient functioning and quality of life will it be possible to determine correctness and professional obviousness of such decisions.