OBJECTIVES: To assess the cost-effectiveness (CE) of switching from insulin glargine ± oral glucose-lowering drugs (OGLDs) to insulin detemir ± OGLDs in people with type 2 diabetes (T2DM) in Saudi Arabia, South Korea and Algeria based on observational data gathered in routine clinical practice. METHODS: The A1chieve®study assessed safety and outcomes over 24 weeks in 66,726 people with T2DM starting insulin analog therapy. The CE analyses included people switching to detemir in Saudi Arabia (n=102), South Korea (n=82) and in 3 North-West African countries (n=94). Data were collected on clinical effectiveness and adverse events, and health-related quality of life using the EQ-5D questionnaire. CE analyses used the IMS CORE diabetes model with 1 and 30 year time horizons, with Saudi Arabia, South Korea and Algeria country-specific costs for complications and therapies and background mortality rates. Incremental cost-effectiveness ratios (ICERs) are expressed as cost per QALY in local currencies, USD and in fractions of local GDP per capita. CE was pre-defined using the WHO definition of <3 times GDP per capita.    RESULTS: The switch was found to be less costly and have better outcomes in South Korea after 30 years and in Saudi Arabia at both time horizons. 1-year ICERs were: Saudi Arabia (SAR -5,849; USD -1,559; GDP -0.08), South Korea (KWR 296,842; USD 273; GDP 0.01), and Algeria (DZD 267,771; USD 3,363; GDP 0.80). 30-year ICERs were: Saudi Arabia (SAR -14,839; USD -3,957; GDP -0.19), South Korea (KWR -1,133,202; USD -1,043; GDP -0.05), and Algeria (DZD 226,818; USD 2,849; GDP 0.68). Sensitivity analyses on the 30 year time horizon showed the findings to be robust. CONCLUSIONS: Switching from glargine±OGLDs to detemir±OGLDs in T2DM as performed in the A1chieve® study was found to be cost-effective across all country settings at 1 and 30 year time horizons.