OBJECTIVES: Combination therapy, with either repaglinide or nateglinide in addition to metformin, is typically initiated in patients with type 2 diabetes unable to achieve glycemic control with monotherapy. The efficacy and safety of treatment with these two therapies in combination with metformin has been evaluated in a head-to-head clinical trial over 16 weeks in type 2 diabetes patients with an inadequate response to sulphonylurea or metformin alone. The study demonstrated that after 16 weeks of therapy, patients treated with Repag+Met had lower HbA1c levels than those treated with Nateg+Met (-1.28% vs -0.67%). METHODS: A published and peer-reviewed model for type 2 diabetes was used in the analysis to project the impact of treatment with repaglinide and nateglinide, on long-term outcomes including life expectancy, quality-adjusted life expectancy and lifetime costs in the Finnish setting. Annual medication costs in each treatment arm were calculated using the median end of trial doses. Direct medical costs of treating diabetes-related complications used in the analysis were collected from published literature. Outcomes were discounted at 5% annually, in line with Finnish recommendations. RESULTS: Repaglinide was projected to increase life expectancy (0.12 years) and quality-adjusted life expectancy (0.11 years) compared to nateglinide. Lifetime costs in patients treated with repaglinide were projected to be € 2627 lower than nateglinide. Improvements in long-term outcomes were attributed to a delayed onset of diabetes-related complications, particularly those associated with retinopathy and nephropathy. CONCLUSIONS: In combination with metformin, repaglinide was projected to be dominant to nateglinide, with improvements in LE, QALE and costs, in the Finnish setting.