Identified the concept of acculturation as a cornerstone of immigration research, while questioning assumptions about zero-sum cultural change in acculturation scales and in procedures assessing biculturality. Involvements in the host society culture and the culture of origin should be assessed separately in order to reflect the complexities of the cultural interactions immigrants and their offspring experience. To evaluate this prescription, we convened focus groups of Puerto Rican adults to discuss their cultural experiences in Puerto Rico and in the United States. Discussions were content analyzed to develop acculturation items. Factor analysis of the responses of 403 first- and second-generation adults yielded two general factors, involvement in American culture and involvement in Puerto Rican culture, which demonstrated modest reliability, relative independence, and moderate correlations with traditional acculturation scale validators. Results of the study challenge the assumption of mutual cultural exclusivity in acculturative change; enable the measurement of degree of biculturality; and provide future directions for the assessment of acculturation in domains other than language usage. The concept of acculturation is integrated with recent formulations in community psychology which advocate a deeper and more extensive commitment to studying the implications of cultural phenomena and greater focus on the growing cultural diversity in the United States.