Purpose: The purpose of this study was to identify preferences of persons with mental illnesses for mental health services. Methods: Q-methodology, an approach designed to discover patterns in various subjective experiences, was used. Twenty-six participants classified 36 selected Q-statements on a nine-point scale to create a normal distribution. The collected data were analyzed using the PC Quanl program. Results: Four types of preference in mental health services for persons with mental illnesses were identified by the participants: Type I Interaction preference type, Type II Patient right seeking type, Type III Clinical environment preference type, Type IV Treatment outcome seeking type. Conclusion: The results of this study provide an understanding that different types of preference for mental health services exist and each type has certain characteristics, which suggest a need to develop practical mental health practice nursing standards designed for each type of preference for mental health services.