Study Objective: Emergency physicians often must deliver medical care with minimal access to historical clinical information. We demonstrate the feasibility and potential value of increased access to patients’ clinical information from another hospital while they are receiving care in the emergency department. Methods: We conducted a pilot randomized, controlled trial of providing information from a large, longitudinal, computer-based patient record system of clinical data from an urban hospital to emergency physicians at either of 2 urban EDs. We randomized patients seen at either ED to have the information from the computer-based patient record system provided to their physician or to not have the information provided. We delivered information to the emergency physician both as a printed abstract and by means of online access to the computer-based patient record. We assessed charges, hospital admissions, repeat visits to EDs, and the emergency physicians’ satisfaction with the information. Results: Under certain assumptions, the intervention was estimated to decrease charges for ED care by approximately $26 per encounter (P =.03) at 1 hospital, but there was no effect on charges at the other hospital. This result was likely because of marked differences in the workflows and information access at these 2 EDs. We demonstrated no differences in admission rates or repeat visits to the ED. Emergency physicians identified that remembering their passwords and the time required to search for the information were significant barriers to accessing clinical information online. Conclusion: Our pilot study is the first to demonstrate the feasibility of sharing clinical information between different health care systems. We observed a trend toward cost savings at 1 of 2 hospitals and no differences in the quality measures we studied. Our experience underscores the difficulties inherent in studying the effects of community-wide health care interventions on cost and quality of ED care. [Overhage JM, Dexter PR, Perkins SM, Cordell WH, McGoff J, McGrath R, McDonald CJ. A randomized, controlled trial of clinical information shared from another institution. Ann Emerg Med. January 2002;39:14-23.]