Though formally included in the Diagnostic and Statistic Manual of Mental Disorders since 1980, dissociation had once been considered as a rare psychiatric disturbance. With standardized structured interview, however, recent empirical studies showed that in average 9 percent of participants in general population, 10 percent in psychiatric outpatients, and 15 percent in psychiatric inpatients receive the diagnosis of a dissociative disorder. In Taiwan few attempts have been made for systematic investigation of dissociative disorders. Little has been known about the characteristics, prevalence, and associated features of Taiwanese patients with a dissociative disorder. The goal of the project is to investigate the prevalence of dissociative disorders in psychiatric inpatients in Taiwan. Relevant clinical issues, including common psychiatric comorbidity (e.g., positive psychotic symptoms), associated psychosocial factors (e.g., negative life events, perceived parenting style), and neuro-cognitive underpinning (e.g., executive functions) were also targeted. Standardized interview schedules, self-report scales, and cognitive tasks will be applied and the assessment will be held by the licensed clinical psychologist who receive training on the assessment and treatment of dissociative disorders. The results may enhance the understanding about the clinical features of dissociative disorders in Taiwan.