This paper describes the development of a measure of ethnic identity among American Indian adolescents. Data were collected in nine high schools in four American Indian communities (N=1,592). The self-report survey included eight ethnic identity questions, seven items about social competencies, eight items on personal mastery and locus of control, six items concerning self-esteem, and six items about perceived social support. Factor analysis identified two major factors resulting in an eight-item Indian scale and a six-item White scale. Analysis found that respondents who identified with both White and Indian cultures tended to have the highest scores on the psychological measures of well-being. Results suggest that the use of this bicultural scale by mental health providers might allow examination of the connections between patterns of ethnic identity and emotional/behavioral problems. (Contains 24 references.) (DB)