Aim To investigate the effectiveness of premixed insulin for achieving glycaemic outcomes in clinical practice in the UK. Materials and Methods Electronic medical record data from The Health Improvement Network database were captured for adults with type 2 diabetes (T2D) uncontrolled (HbA1c ≥9%) on two or more oral antihyperglycaemic drugs (OADs) initiating premixed insulin. Effectiveness of premixed insulin was assessed by the probability and incidence of achieving glycaemic outcomes (target HbA1c 40 kg/m2 and co‐morbidities including nephropathy and stroke. Conclusions In people with uncontrolled T2D (HbA1c ≥9%), glycaemic outcome achievement on premixed insulin was low at 6 months with little additional clinical benefit beyond 12 months, suggesting a high unmet need for early, timely treatment changes with more effective, simpler therapies.