BACKGROUND: Congress has authorized the United States Food and Drug Administration (FDA) to provide industry sponsors with a 6-month extension of drug marketing rights under the Pediatric Exclusivity Provision if FDA-requested pediatric drug trials are conducted. The cost and economic return of pediatric exclusivity to industry sponsors has been shown to be highly variable. We sought to determine the cost of performing pediatric exclusivity trials within a single therapeutic area and the subsequent economic return to industry sponsors. METHODS: We evaluated 9 orally administered antihypertensive drugs submitted to the FDA under the Pediatric Exclusivity Provision from 1997 to 2004 and obtained key elements of the clinical trial designs and operations. Estimates of the costs of performing the studies were generated and converted into after-tax cash outflow. Market sales were obtained and converted into after-tax inflows based on 6 months of additional patent protection. Net economic return and net return-to-cost ratios were determined for each drug. RESULTS: Of the 9 antihypertensive agents studied, an average of 2 studies per drug was performed, including at least 1 pharmacokinetic study and a safety and efficacy study. The median cost of completing a pharmacokinetic trial was $862,000 (range $556,000 to 1.8 million). The median cost of performing safety and efficacy trials for these agents was $4.3 million (range $2.1-12.9 million). The ratio of net economic return to cost was 17 (range 4-64.7). CONCLUSION: We found that, within a cohort of antihypertensive drugs, the Pediatric Exclusivity Provision has generated highly variable, yet lucrative returns to industry sponsors.