This paper is designed to assist forensic psychiatrists/psychologists who evaluate adults who commit sexual crimes against children on the Internet. The typical offender is an adult male who logs onto the Internet and enters a chat room in which children congregate. Unbeknownst to the offender, undercover police officers are posing as minors in the chat rooms. The undercover officer (pretend kid) and offender engage in increasingly explicit, sexual conversation; the offender may transmit erotic photographs to the undercover officer and/or arrange to meet at a motel in order to have sexual intercourse. The authors will discuss the relevant legal, clinical, and ethical aspects of examining these offenders, and describe specific cases that the author (2) evaluated.