The Critical Incident Team (CIT) training program equips police officers with knowledge regarding mental illness and practical skills for effectively interacting with a mentally ill suspect. In addition to improving officer and suspect safety by decreasing the number of violent encounters between police and the mentally ill, CIT goals include reducing the number of mentally ill individuals who are arrested and providing them with assistance through community resources. However, there is a lack of empirical research on whether CIT training decreases arrest rates and increases diversion rates for mentally ill subjects. The purpose of this quantitative study was to measure the effects of CIT training on arrest and diversion rates of mentally ill subjects. The theoretical foundation for the study was evidence-based policing. Reports from a single police department in the southwestern United States were reviewed, and arrest and diversion incidents from 6-months pre and post CIT training for 30 police officers were collected. A paired-samples t test was used to analyze the data, which indicated that there was not a statistical difference in arrest rates or diversion rates between pre and post CIT training. Results corroborated the findings of other studies showing that arrest and diversion rates are not affected by CIT programs. Law enforcement agencies that currently have or are looking to implement a CIT program may find the study useful, as it reports an increase in resources being provided to mentally ill subjects following contact with a CIT officer. Recommendations include additional research into the effectiveness of the CIT program as well as the continuation of collaboration between community mental health organizations and police, both of which may lead to positive social change.