This article examines the importance of criminal informants to law enforcement investigations and how the concept of disloyalty functions in this arena. The article has three main sections. The first portion of the article presents a philosophical discussion of the concepts of loyalty and disloyalty, the value of loyalty, and the moral status of disloyalty. The discussion centers on the contradiction between the need for law enforcement to use criminal informants and the criminal informants' need to be disloyal to their organizations in order to be a successful informant, and society's reaction to this contradiction. The second section of the article presents three scenarios that examine the concept of disloyalty in specific informant situations: the criminal who provides information about an accomplice to the police; specific communities that discourage their members from assisting the police; and informing in parts of society where specific community pressures against informing do not exist. Following this discussion of loyalty/disloyalty, the author presents three policy recommendations for use by police departments, prosecutors' offices, and legislators: 1) the development of explicit consideration of loyalty/disloyalty issues in police and prosecutorial guidelines regarding the use of informants; 2) consideration of community-specific norms in the use of informants, especially in communities with strong anti-cooperation moral codes; and 3) restriction on the creation and enforcement of minor offenses the encourage citizens to inform on those who commit minor violations.