OBJECTIVES: To calculate cost-effectiveness ratios [incremental cost per quality-adjusted-life-year (QALY) gained] for somatropin (Genotropin®) treatment of adult patients with growth hormone deficiency (GHD) due to non-functioning pituitary adenoma compared to no growth hormone replacement treatment. METHODS: A Markov-type cost-utility simulation model was constructed and used in order to simulate, for a male and female cohort, morbidity and mortality for treated and not treated individuals over a 20-year time horizon. The calculations were performed using 2003 prices concerning morbidity-related healthcare costs, and up-to-date unit cost for Genotropin®. Costs are expressed in SEK (I Euro = 9.5 SEK). All costs and effects are discounted at three percent. The total of 550 treated Swedish patients from the KIMS database (Pfizer International Metabolic Database) was used in the calculations.     RESULTS: The results are presented as incremental cost per QALY gained including both direct and indirect effects and costs. The weighted sum of all sub-group incremental cost-effectiveness ratios (excluding indirect effects of mortality), were SEK141,650 (€14,911) and SEK206,028 (€21,687) for men and women, respectively. Including also indirect mortality effects resulted in lower weighted cost-utility ratios: SEK131,474 (€13,839) and SEK150,766 (€15,870) for men and women, respectively. Key drivers of the results are improvement in quality of life, increased survival and treatment cost. CONCLUSIONS: The results show that the overall cost per QALY is moderate if compared to informal thresholds applied in Sweden. Our simulations suggest that at the SEK500,000 (€52,632)/QALY-threshold, treatment with Genotropin® has a 100% probability of being cost-effective for men and at least 90% for women.