Insulin glargine (Abasaglar®) is recommended as an option for restricted use within NHS Wales for the treatment of diabetes mellitus in adults, adolescents and children aged 2 years and above. Insulin glargine (Abasaglar®) should be prescribed within its licensed indication in accordance with NICE or AWMSG guidance for insulin glargine (Lantus®), the reference product. Insulin glargine (Abasaglar®) is not recommended for use within NHS Wales outside of these circumstances. Insulin glargine (Abasaglar®) should be prescribed by brand name to avoid automatic substitution and therefore help with pharmacovigilance.