Despite increased sharing of decisionmaking responsibilities between the mental health and criminal justice systems, confusion and inadequate communications characterize most interactions. Therefore, a definition of forensic mental health screening and evaluation is presented here as a conceptual foundation for highlighting the points of interaction between the two systems. In general, screening and evaluation is a process conducted by mental health personnel at the direction of criminal justice authorities for the purpose of delineating, acquiring, and providing information about the mental condition of client-offenders. The information obtained from the process is used by decisionmakers in the criminal justice system. Mental health personnel may be psychiatrists, clinical psychologists, social workers, and other specified professionals. Clients are individuals who are convicted criminals or alleged offenders whose mental condition has been questioned. Usually, the information is used to determine whether such individuals should be handled by the criminal justice system or diverted, either permanently or temporarily, into the mental health system. The delineation of screening and evaluation can be significantly improved by an exchange of memoranda or meetings between referral agents (e.g., judges) and mental health examiners. These exchanges could serve to specify such client factors as type of offense, age, race, and history of substance abuse. In addition, aspects of written reports, time frames for completion of screening, and mechanisms for conveying the request for evaluation could be clarified. Communication between court personnel and mental health workers enhances the benefits to the client. Eighteen reference notes are provided.