Teh main purpose of this study was to investigate attitudes toward mental illness and the mentally ill of psychiatric nurses in Korea and to identify the relationships between the nurses' attitudes and demographic variables. Subjects in this study were 122 psychiatricnurses and 111non-psychiatric nurses in active service at 12 hospitals in Seoul. The insrtument used for measuring attitudes was a questionaire developed by Cohen and Struening (1962) referred to as the "Opinions about Mental Illness(OMI) Scale" made up to 51 Likert type items. The findings of this study indicated hatnurses showed negative attitudetoward mental illness and the mentally ill: Very high on social restrictiveness (factor D), low on Mental Health Ideology (factor C), and Interpersonal Etiology (factor E). Since the high score on Factor A,B and the low score on Factor B,C,E reflect a negative attitudes toward mental illness, this study population related extremely negative attitudes compared to any other surveys. And of the demographic variables that related to their attitudes the education degree and the kind of the hospital in active service showed very significant differences. On the basis of the investigation the findings indicated the followings; 1) Althohg attitudes toward mental illness and the mentally ill of psychiatric nurses were not siignificant differences from non-psychatric nurses, there was a trend that attitudes of psychaitric nurses did show more negative responses rather than those of non-psychiatric nurses. 2) Demographic variables that relate to their attitudes on the OMI scale were the education degree of the respondent and the kind of their hospital in active service. 3) About attitudes toward mental illness and the mentally ill baccalaureate nursesshowed more posttive attitudes in Factor A (Authoritarianism), Factor C (Mental Health Ideology) and Factor D (Social Restrictiveness) than diploma program murses. 4) Nurses in active Service in the private hospital revealed more positive attitudes(A,B,C,D) except Factor (E) than those in the national or public hospital. 5) The ages, duration of work, wanted or unwantedG roup of psychiatric ward and satisfactory level of psychiatric nursing service were non-significant.