AIM: To compare pre-meal injection of Humalog Mix50 (Mix50) and Humalog Mix25 (Humalog Mix75/25 in the US; Mix25) with respect to 2 h postprandial (2 h pp) blood glucose (BG) control after a carbohydrate-rich breakfast in patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: One hundred and sixteen patients were enrolled in a 16-week crossover trial and received two treatment regimens in a randomized crossover fashion: (i) Mix50 before breakfast and Mix25 before the evening meal (Mix50/Mix25) and (ii) Mix25 before both breakfast and the evening meal (Mix25 twice daily). Insulin doses were adjusted according to stated glycaemic targets. After 6 and 8 weeks of treatment, the patient's usual morning insulin dose was administered, followed immediately by a test breakfast representative of the patient's usual breakfast meal. Fasting and 2 h pp BG concentrations were measured at the time of the test meal. Haemoglobin A1c (A1C) was measured, and information regarding hypoglycaemia (symptoms) was collected at the end of each treatment period. RESULTS: Insulin doses were similar between treatments (morning = 31-33 U, evening = 26-28 U) at endpoint. Following the test breakfast, the 2 h pp BG was lower (10.9 +/- 0.3 mmol/l vs. 12.4 +/- 0.3 mmol/l, p = 0.0012) and the 2 h pp BG excursion was smaller (1.4 +/- 0.28 mmol/l vs. 3.5 +/- 0.28 mmol/l, p < 0.001) during treatment with Mix50/Mix25 than during treatment with Mix25 twice daily. There was no difference between the treatments with respect to fasting BG (Mix50/Mix25, 9.5 +/- 0.3 mmol/l vs. Mix25 twice daily, 8.9 +/- 0.3 mmol/l; p = NS), A1C (8.14% +/- 1.14% vs. 8.14% +/- 1.07%; p = NS) or the incidence of self-reported hypoglycaemia (34% vs. 23%; p = NS). CONCLUSIONS: Compared with treatment with Mix25 twice daily, treatment with Mix50 before breakfast and Mix25 before the evening meal resulted in better pp glycaemic control following a carbohydrate-rich meal, and similar fasting BG, A1C and incidence of hypoglycaemia in patients with type 2 diabetes.