Patient's decision making competence (PDMC) is a widely discussed subject. Issues of competence, autonomy, well-being and protection of the patient come up every day. In this article we analyse what role PDMC plays in Dutch legislation and what dilemmas healthcare professionals may experience, notably in patients suffering from Korsakoff's syndrome. Dilemmas emerge if professionals want to meet the requirements mentioned in Dutch law and the desires of their patients. The autonomy of the patient and the healthcare professionals' duty to take care of their patient's best interests, create a tension and lead to uncomfortable situations. Healthcare professionals describe difficulty finding a balance between these issues and assessing the degree of mental competence still present. In long term care situations, quality of the relationship between healthcare professionals and their patients seems to be of much more importance in decision making on minor issues of competence than simply relying on legal or house rules. In being committed to their cases, professionals will be more sensitive to individuals habits, abilities, welfare and dignity, which will make it easier to decide on issues of competence, and to find creative solutions to their dilemmas.