The purpose of the study was to describe the views of the nursing staff working with long-term psychiatric patients about the patient's right of self-determination. The information obtained was used for clarifying the concept of self-determination and the patient's right of self-determination during hospital care. The research material was collected from the trained personnel (n = 127) working in the long-term or rehabilitation wards of four psychiatric hospitals in the province of south-western Finland. The main method used for collecting the information was a questionnaire containing open questions. The material was processed by analysing the contents with both qualitative and quantitative methods. The nursing staff was able to define the concept of long-term psychiatric patient's right of self-determination quite clearly. On the other hand, the nursing staff did not have a clear idea of how the self-determination was carried out in practice. More than half of the nursing staff consider the self-determination important. Many of them were of the opinion that a patient in a psychiatric hospital has rather little self-determination. The main reason for this is the nature of the patient's illness. Self-determinations is promoted by details connected to the treatment given and the recent development in the treatment.