This trial compared the efficacy and safety of basal-bolus therapy using either the soluble basal insulin analogue insulin detemir (IDet) in combination with meal-time rapid-acting analogue insulin aspart (IAsp), or NPH insulin (NPH) in combination with meal-time regular human insulin (HSI). This was a 22-week, multinational, open-labelled, symmetrically randomised, parallel group trial including 395 people with type 2 diabetes (IDet + IAsp: 195, NPH + HSI: 200). At 22 weeks, HbA1c was comparable between treatments (IDet + IAsp: 7.46%, NPH + HSI: 7.52%, P = 0.515) with decreases from baseline of 0.65% and 0.58%, respectively. Treatment with IDet + IAsp was associated with a significantly lower within-person variation in self-measured fasting plasma glucose (FPG) (SD:1.20 versus 1.54 mmol/L, p < 0.001), as well as a lower body weight gain (0.51 versus 1.13 kg, p = 0.038) than with NPH + HSI. The risk of nocturnal hypoglycaemia was 38% lower with IDet + IAsp than with NPH + HSI, but statistical significance was not attained (P = 0.14). The overall safety profile was similar between the two treatments. Basal-bolus treatment with IDet + IAsp is an effective and well tolerated insulin regimen in people with type 2 diabetes, resulting in glycaemic control comparable to that of NPH + HSI, but with the advantages of less weight gain and a lower day-to-day within-person variation in FPG.