In the juridical and ethical literature on patient selection criteria it is an unargued premise that those who are most urgently in need of treatment or care will be given priority. The aim of this study is to gain insight into the medical practice of waiting list problems and patient selection at the microlevel, especially with respect to urgency. Thus, the study intends to contribute to the medical ethical discussion on patient selection for scarce resources. The results of qualitative research into the meaning and occurrence of urgency in two health care services, renal transplantation and psychogeriatric nursing home care, are discussed. In the first sector, patients are seldom considered urgent. Criteria for urgency are technical dialysis problems or severe psychological burden due to protracted dialysis treatment. In contrast, psychogeriatric patients are often considered urgent, with the principal criterion being too heavy a care load for informal carers. Both health care services show variation in assigning urgency codes. It appears that the exact meaning of urgency is not self-evident and that admission of urgent patients to nursing homes can be negotiated by professionals or informal carers. This points to the necessity of a discussion within these services as to the actual content matter of urgency. Further, professionals involved in renal transplantation raise several moral and practical arguments against giving patients priority, even if they need treatment urgently. It shows that distributive justice cannot always be applied. Occasionally non-urgent patients are rated urgent as they have been waiting very long due to specific allocation procedures. In these cases urgency is granted in an unexpected way that is ultimately in accordance with the notion of procedural justice.