An analysis of the increase in expenditures for barrier isolation materials before and after the institution of universal precautions at our 900-bed university hospital was used to generate a national estimate of the cost of implementation of the new Centers for Disease Control guidelines. Following the institution of universal precautions, use of rubber gloves at our hospital increased from 1.64 million pairs to 2.81 million pairs annually. A 5-year review of hospital purchasing and supply records in both inpatient and outpatient areas indicated that the total annual costs for isolation materials increased by $350 900. This represented an increase from $13.70 to $22.89 per admission (60%) after adjustment for inflation. The cost of isolation materials increased from $98 to $215 per 1000 outpatient visits, an adjusted increase of 92%. Two thirds of the increase (64%) was due to rubber gloves and an additional 25% was due to disposable isolation gowns. Universal precautions are estimated to have cost at least $336 million in the United States in fiscal year 1989 after adjustment for inflation. If expenditures for isolation materials at our medical center are representative, previous estimates may have significantly underestimated costs nationwide.