This article looks at the relevance of the concept of self-determination to psychiatric patients by studying the existence, importance and manifestations of self-determination. The data were collected by interviewing long-term patients (n = 72) in one mental health care organization, which included a psychiatric hospital and an outpatient department. Self-determination was defined in terms of the right to decision-making, the right to information, the right of consent, the right to refuse treatment, and the right to be heard and taken into account. It was found that, with the exception of the right to refuse and consent, these rights are indeed present in the practice of psychiatric nursing and that they are relevant, and important to psychiatric patients. The patients typically gave ethical practical and legal reasons for a psychiatric patient's right to self-determination. The main reasons why psychiatric patients said they lacked the right to self-determination were illness and staff authority. Recommendations for educational, clinical and methodological implications for the future in nursing are discussed.