Handheld computers are being proposed as a resource for ambulatory care, yet physician reluctance to use the devices in the presence of patients is reported to be a barrier to optimal use. This study examined patient attitudes toward the use of handheld computers and the impact of those attitudes on the physicians' use of the handheld computers in the patient care setting. Most patients hold favorable attitudes toward physician use of handheld computers. Providing these data to physicians, however, did not uniformly lead to significant increases in handheld use in the presence of the patient. More understanding of the factors that influence behavior change and methods that will decrease barriers to the use of handhelds is needed