Objective: Insulin degludec/insulin aspart (IDegAsp) is a soluble co-formulation of IDeg and IAsp. This pan-Asian, 26-week trial investigated efficacy and safety of IDegAsp vs biphasic insulin aspart 30 (BIAsp 30) in Asian adults (n = 424) with type 2 diabetes (T2DM), inadequately controlled on once- or twice-daily (BID) basal, premixed or self-mixed insulin. Korean subgroup data was analysed from this pan-Asian trial. Methods: About one-third of the randomised subjects (132 out of 447) were Korean. They were randomised 2:1 to BID IDegAsp (n = 86) or BIAsp 30 (n = 45), and continued existing metformin treatment. Insulins were administered with breakfast and main evening meal, titrated to a pre-breakfast and pre-main evening meal self-measured plasma glucose target of 4~5 mmol/L. As the subgroup analysis was not powered to confirm non-inferiority in the Korean subset, the results are presented using descriptive statistics only. Results: Korean subjects had mean values of age 58.9 years, HbA1c 8.5%, FPG 7.9 mmol/L and BMI 25.6 kg/m2. IDegAsp and BIAsp 30 reduced HbA1c to the same extent (1.5 % vs. 1.5%). Fasting plasma glucose (FPG) was lowered by 2.3 mmol/L in IDegAsp, and 1.9 mmol/L in BIAsp 30. Final mean daily insulin dose was numerically lower in the IDegAsp group than that of the BIAsp 30 group (58 IU vs. 71 IU). Rates of overall confirmed and severe hypoglycaemia were similar between treatments, while rate of nocturnal confirmed hypoglycaemia was numerically lower with IDegAsp (25.6% vs 31.8%). The Korean subset analysis was generally consistent with the total trial results. Conclusion: Korean T2DM adults showed the consistency with the total population. Compared to BIAsp 30, IDegAsp BID effectively improves long-term glycaemic control, provides superior reductions in FPG with a lower dose, and numerically reduced nocturnal hypoglycaemia.