OBJECTIVES: To measure healthcare costs for patients receiving repaglinide, metformin, repaglinide/metformin, and glyburide/metformin within a managed care organization (MCO). METHODS: Using retrospective pharmacy and medical claims from a MCO, adult patients with type 2 diabetes identified during CY2000 were stratified into the following cohorts based on their medication regimen at identification date: repaglinide only (n=500), metformin only (n=26,535), repaglinide/metformin (n=172), glyburide/metformin (n=17,160). Pharmacy, medical, and total (pharmacy + medical) healthcare costs were measured for each cohort over a 9-month period. Costs were adjusted for age, gender, and comorbidities using Analysis of Covariance. RESULTS: Adjusted pharmacy costs were lowest for patients receiving metformin only ($1182; 95% CI $1172 - $1191), followed by metformin/glyburide ($1339; 95% CI $1327 - $1351), repaglinide only ($1518; 95% CI $1447 - $1588), and repaglinide/metformin ($1,936; 95% CI $1,816 - $2,056). Differences between the cohorts in adjusted medical and total healthcare costs were not statistically significant. Adjusted medical charges were $6,988 for repaglinide/metformin, $8,236 for metformin/glyburide, $8,267 for metformin only, and $10,392 for repaglinide only. Total adjusted healthcare costs were lowest for repaglinide/metformin ($8,924), followed by metformin only ($9,448), metformin/glyburide ($9,576), and repaglinide only ($11,910). CONCLUSIONS: Although not statistically significant, repaglinide/metformin yielded lower total healthcare costs than metformin alone, metformin/glyburide, or repaglinide alone. While these results need to be confirmed using larger patient populations, they imply that differences in pharmacy costs of repaglinide/metformin therapy are offset by measurable medical cost savings.