The survey questionnaire was mailed to 3,118 law enforcement agencies. The 2,945 agencies that responded included 424 municipal agencies with more than 100 sworn officers. The analysis focused on hazardous duty pay, differential shift pay, education incentive pay, and merit pay in these 424 agencies. The data were analyzed by means of logistic regression techniques. Results revealed that the existence of a collective bargaining mechanism in these large police agencies was significantly correlated with the presence of supplemental pay benefits that were favorable to police officers. Findings were consistent with previous research on the impact of collective bargaining on the salary levels in police agencies. The effect was small or moderate, but it was fairly consistent on predicting hazardous duty pay, shift differential pay, and education incentive pay, all of which are strongly endorsed by police unions across the country. Results also revealed that geographic region accounted for about 38 percent of the variance and that each region was relatively unique in terms of the presence of these pay benefits. Thus, the effective of collective bargaining is very limited if regional differences are taken into consideration. Tables, notes, and 27 references