Objective: A pooled analysis of three clinical trials showed the therapy benefits of treating type 1 diabetic patients (mean age 40.3 years, duration of diabetes 16.3 years, HbA1c 8.3%, BMI 25.2 kg.m-2) with insulin detemir (IDet) versus neutral protamine Hagedorn (NPH) insulin as the basal component of basal-bolus therapy when used in combination with either insulin aspart (IAsp) or human soluble insulin (HSI). The analysis demonstrated a short-term improvement for detemir over NPH in HbA1c (0.13% points lower), a decrease in hypoglycemic events (by 4%) and lower body mass index (BMI) (0.21 kg.m-2). Methods: A published validated diabetes model was used to estimate the long-term cumulative incidence of complications, life expectancy (LE), quality-adjusted life expectancy (QALE) and lifetime costs for IDet versus NPH regimens. Treatment pattern and costs in the Portuguese setting were taken from published sources and validated with clinical experts. All outcomes were discounted at 5% annually. Results: The IDet arm was associated with an increase in life expectancy, compared to NPH, of 0.062 years with a resulting gain in QALE of 0.184 quality-adjusted life years, QALYs (±SD) (6.3±0.06 versus 6.12±0.06 QALYs) due to a reduction in diabetes-related complications. Increased treatment costs for IDet resulted in greater total lifetime costs per patient than with NPH (€37,760±743 versus €33,403±738), leading to an incremental cost-effectiveness ratio of €23,691 per QALY gained. The results were robust when tested for parameter sensitivity. Cost-effectiveness acceptability with a threshold of €50,000 is 90%. Conclusion: Short-term improvements seen with IDet versus NPH in basal-bolus therapy were projected to show improvements in quality-adjusted life expectancy with a cost-effectiveness ratio which fell well within the range usually considered acceptable value for money.