BACKGROUND: Adults frequently seek medical services in children's hospital emergency departments (CHEDs), and are required to be admitted to CHEDs under the provisions of the Emergency Medical Transfer and Active Labor Act (EMTALA), which requires medical evaluation and stabilization of every patient who presents to an emergency department. In recent years visits by adults to CHEDs appear to have increased. OBJECTIVE: There were 3 objectives to the current study: 1) to examine secular trends in the number of adult patients visiting CHEDs, 2) to determine if perceived increases are related to the implementation of EMTALA, and 3) to examine the characteristics, evaluation, and disposition of adult patients presenting for first-time visits to a CHED. METHODS: A database of all visits to an urban CHED between 1992 and 2002 was queried to collect information on adult patients (22 years or older). New adult patients were identified based on the assignment of new medical record numbers. The medical records of all adult patients presenting during the 1-year interval before and after the institution's full implementation of EMTALA were reviewed and relevant data collected. RESULTS: Over the study period, there were 501,033 patient visits to the CHED. Of these, 5512 (1.1%) were by adult patients, which included 536 (9.7%) new adult patients. Using the chi(2), test we found a significant increase in the total number of adult visits and the number of new adult visits, particularly after the implementation of EMTALA. The mean age of the new adult patients was 34.9 +/- 11.9 years. Their most frequent chief complaints were injuries (24.4%), cardiac-related problems (7.6%), and syncope (6.7%). A total of 427 (79.7%) of the new adult patients were treated and released, 81 (15.1%) were transferred to an outside hospital for additional care, and 15 (2.8%) were admitted to our hospital. There were no significant differences between the new adult populations in 1997 and 1999. Comparing new and established adult populations in 1999, the population of new adults was significantly older (28.1 +/- 6.8 vs 34.9 +/- 11.9 years) and more likely to present with injuries or syncopal episodes. Among the total cohort of new adult patients in the study, chest pain also occurred at a significantly higher rate compared with established adults (6.7% vs 3.8%). CONCLUSIONS: Adult visits to CHEDs appear to be increasing in frequency in association with the implementation of EMTALA regulations. It is therefore essential that physicians staffing CHEDs be properly trained in the stabilization of common adult medical emergencies. We recommend that the language of EMTALA be revised to allow adult patients with nonemergent problems to be directly referred to adult emergency departments, which are more appropriate than CHEDs.