We estimate the medical cost per life-year gained from increased utilization of HIV drugs by estimating the impact of increased drug utilization on the life expectancy and drug and hospital expenditure of HIV/AIDS patients, using aggregate (U.S. national-level) data for the period 1982-2001. We use IMS Health data on the aggregate number of and expenditure on HIV drug prescriptions, the CDC%u2019s AIDS Public Information Data Set, and data from AHRQ%u2019s Nationwide Inpatient Sample. Estimates of mortality models imply that actual life expectancy of HIV/AIDS patients in 2001 was 13.4 years higher than it would have been if the drug utilization rate had not increased from its 1993 level. Estimates of a model of hospital discharges imply that increased utilization of HIV drugs caused hospital utilization to decline by .25 to .29 discharges per person per year during the period 1993-2001. Medical cost per additional life-year is estimated to have been $17,175. Treatments that cost this amount are widely considered to be cost-effective. The consistency of this estimate with those from previous studies suggests that analysis of aggregate data may be a useful alternative or additional approach to evaluating the cost-effectiveness of new treatments.