This article reports the findings from a study that investigates predictors of police willingness to blow the whistle and police frequency of blowing the whistle on seven forms of misconduct. It specifically investigates the capacity of nine policy and structural variables to predict whistle-blowing. The results indicate that two variables, a policy mandating the reporting of misconduct and supervisory status, surface as the most consistent predictors of whistle-blowing. Contrary to popular belief, the results also show that police are slightly less inclined than civilian public employees to subscribe to a code of silence. (Contains 6 tables and 4 notes.)