Field survey data were obtained from police and probation officers in Nassau County, N.Y., Albuquerque, N. Mex., and San Jose, Calif. Research demonstrated conflicts between police and probation officers in four dimensions: criminal justice goals, status and professional esteem, operational approaches, and perceptions of each other's actions and goals. Study instruments assessed operational characteristics, political and legal viewpoints, status attitudes, and interagency contact. Respondents were asked to evaluate typical incidents of police-probation conflicts and estimate average responses. Most contact was by telephone; probation officers initiated most calls. Conflicts reflect differing political ideologies and work attitudes. Probation officers were more likely to have civil libertarian and rehabilitative philosophies; they often distrusted police officers' social code and political conservativism. Both groups believed that society attaches more importance to probation officers than to police; both exaggerated their differences. Group discussion and increased interaction between agencies help reduce friction. Tabular data, notes, and a bibliography of more than 250 references are supplied; study instruments are appended.