Puerto Rican adolescent ego identity development was studied within the frameworks of Erikson's psychosocial theory and Heller's conceptualization of familism. Ego identity was measured by the Revised Version of the Extended Objective Measure of Ego Identity Status-2, an instrument based on Erikson's theoretical formulations. The Heller's Familism Scale was utilized to measure familism. It was hypothesized that there is a relationship between familism and the four identity statuses: achievement, moratorium, foreclosure, and diffusion. It was also hypothesized that familism, gender, age, parent's education and occupation, and number of years living in the United States mainland affect an individual's identity status. There were two sample groups; one living in Puerto Rico (n= 180), and one living in Florida (n= 107). Correlations and multiple regression analyses were utilized to test the hypotheses of this study. The regression analysis showed that the independent variables, age, parental level of education, familism, and, for the immigrant group, number of years living in the United States mainland help explain the variance in some of the statuses scores. Some of the variance in the achievement scores can be explained by the independent variables for immigrant male and female adolescents. The independent variables helped explain the variance in the moratorium scores of the male adolescents living in Puerto Rico, and both male and female immigrant adolescents. The variance in foreclosure scores could only be explained by the independent variables when the subjects were female immigrant adolescents. Finally, the independent variables helped explain the variance in the diffusion scores for the female subjects, regardless of sample group. An analysis of variance revealed a main effect for gender in achievement scores, and diffusion scores. ANOVA also revealed a Significant difference among the subject groups diffusion scores. ANOVA identified a significant interaction between gender and sample group for the foreclosure status. Furthermore, ANOVA revealed a significant difference between male and female foreclosure scores. Also, ANOVA revealed a significant difference between sample groups. Because the independent variables explain only a small percentage of the variance in the four ego identity status scores, caution should be exercised in arriving at conclusions about the relative importance of the independent variables on ego identity. / Ph. D.