Decertification is the process by which a State authority determines that an individual should not be allowed to continue exercising the duties and privileges of a law enforcement officer. This is a potentially powerful mechanism for ensuring integrity in law enforcement, yet little is known about the nature and scope of decertification actions. This article presents the findings of a national study of decertification practices among the States. Over 1,350 officers were decertified during 2011 including corrections officers, police officers, and others, and the base rate of decertification among police officers is estimated to be 1.2 per 1,000 officers, varying from zero to 7.6 per 1,000 at the State level. Sources of variability and policy implications are discussed. Abstract published by arrangement with Sage Journals.