Conscientious sign-out between medical interns is important for the continuity of care of hospitalized patients. We developed a standardized sign-out card that prompted the intern going off duty to transmit patient care information to the inter on call. The card was tested in a prospective, randomized, controlled trial in which one group of interns used the card, and another group did not. Any instance of poor sign-out was reported on a questionnaire completed by the intern who had been on call the previous night. The group using the sign-out cards reported poor sign-out on 8 nights (5.8% of questionnaires), and the control group reported it on 17 nights (14.9% of questionnaires, p = .016). The card was time-effective and inexpensive, resulted in more complete data recording, and possibly decreased the morbidity associated with poor sign-out.