Questionnaires were administered to police officers representing six law enforcement agencies in Idaho and Washington, with three agencies from predominantly rural communities and the other three in suburban communities. To measure professionalism, five dimensions were rated on a scale: (1) use of the professional organization as a major reference, (2) belief in public service, (3) belief in autonomy, (4) belief in self-regulation, and (5) sense of calling in the field. Results suport the contention that commitment to a professional ideology reduces role conflict among police. However, only particular dimensions produce such effects. For rural police departments, belief in self-regulation was shown to be the dominant variable. For urban police departments, belief in self-regulation, sense of calling to the field, and belief in autonomy were viewed as reducing role conflict. The dominance of belief in self-regulation in both rural and urban police departments points to police officers' narrow conception of professionalism, which emphasizes specialization of police work, and the perception that only colleagues are qualified to judge their work. Moreover, the differential pattern in effects of the professionalism dimensions for the rural and urban police departments indicates that organizational type conditions the impact of professionalism. Rural location implies both a lower volume of crime and more knowledge of local citizens; thus, a 'service style' of activity and organization is warranted. In contrast, the urban police officers' evironment is characterized more by anonymity and heterogeneity, so that autonomy and sense of calling are more salient concerns. Overall, results indicate that role conflict may be reduced through police professionalization, but that the influence of professionalism is conditioned by department type. Eighteen references and several tables are provided.