Introduction: 911 centers receive a wide variety of calls for police-related incidents. Using the Police Priority Dispatch System (PPDS ® ), a 911 Emergency Police Dispatcher (EPD) categorizes each incident with a specific Chief Complaint (CC) and prioritizes the case using a systematic alpha-numeric coding matrix. The wide variation in CC types and specific codes assigned can profoundly affect staffing and resource deploy ment decisions made by law enforcement agencies. However, the frequency of specific call types and priority levels in the PPDS has not been studied formally to date. Objective: The objective of this study was to quantify and describe the distribution of PPDS CCs, priority levels, and specific incident codes using dispatch data from two 911 centers in North America. Also, we aimed to identify the five most frequently used CCs. Methods: This was a retrospective and non-controlled descriptive study involving two emergency communication centers in North America. Descriptive statistics such as frequencies and percentages were used in the tabulation of incidents of calls by Chief Complaint and Determinant Code, by agency, and overall. Results: A total 541,172 call records were collected, using PPDS v3.0 (2001-2008 release) using the ProQA software program logic engine. Overall, across these two centers, the five most frequently used PPDS CCs were Protocol 113 (Disturbance/ Nuisance) (22.6%), Protocol 131 (Traffic/Transportation Incident [Crash]) (12.7%), Protocol 130 (Theft [Larceny]) (12.5%), Protocol 114 (Domestic Disturbance/Violence) (7.2), and Protocol 129 (Suspicious/Wanted [Person, Circumstances, Vehicle]) (7.0%). Similar patterns were observed in each agency. The majority of the calls were coded at the DELTA level, followed by the BRAVO level. Conclusions: 911 Emergency Police Dispatchers using the PPDS assign a wide range of CCs, priority levels, and Determinant Descriptor codes. The five most frequently used CCs were Disturbance/Nuisance, Traffic/Transportation Incident (Crash]), Theft (Larceny), Domestic Disturbance/Violence and Suspicious/Wanted (Person, Circumstances, Vehicle). Future studies should examine meaningful case outcome measures by priority level and complete determinant code, and should also investigate the reasons for differences observed between systems and agencies.