Study subjects were 407 police officers selected from the ranks of three large city and two small city police agencies. A questionnaire was developed to measure differences in police discretion. The first section of the questionnaire requested demographic information, while the second section consisted of eight situational vignettes involving police encounters with traffic or domestic problems, public intoxication, and disorderly conduct. Study results indicated a significant disparity in how police officers implement their discretionary decisionmaking to arrest or not arrest in nonfelony and mid-level offenses involving similar situations. Results also revealed that offender race strongly influenced the decisionmaking process; police had a tendency to take more punitive actions against black offenders than white offenders. Police in urban areas demonstrated the greatest disparity in the use of personal discretion. Because none of the police agencies had any type of enforcement policies or guidelines to aid their officers in the performance of their duties, individual officers had ample opportunity to inject their own prejudices or legal interpretations into job performance. 3 references, 9 figures.