AIMS/HYPOTHESIS: The aim of this prospective trial was to compare the effect of different long-acting insulin preparations injected at bedtime on glucose concentrations in patients with type 2 diabetes omitting breakfast and lunch the next day. METHODS: Twenty patients (ten women) with type 2 diabetes who were on an intensified insulin therapy participated. Mean (+/-SD) age was 63 +/- 10 years, diabetes duration 18 +/- 9 years, BMI 32.5 +/- 5 kg/m(2), and HbA(1c) 7.3 +/- 0.7%. Patients received neutral protamine Hagedorn (NPH) insulin, insulin detemir or insulin glargine for at least 2 months; doses were adjusted to achieve morning blood glucose levels of <7 mmol/l. At the end of the respective treatment period, the long-acting insulin was injected at bedtime (at 22:45 hours) as usual but patients refrained from breakfast and lunch the next day; glucose was measured by a continuous glucose monitoring system (CGMS). RESULTS : Comparable glucose target ranges were reached at midnight (5.8 to 6.1 mmol/l) and at 07:00 hours (6.7 to 6.9 mmol/l) with all three insulin preparations, using mean doses of 29 +/- 10 U (NPH insulin), 33 +/- 13 U (insulin detemir), and 32 +/- 12 U (insulin glargine). Glucose levels between midnight and 07:00 hours were not significantly different for the three insulin preparations. Symptomatic hypoglycaemia did not occur from 08:00 to 16:00 hours; glucose concentrations during this time were slightly lower with NPH insulin than with insulin detemir (p = 0.012) and insulin glargine (p = 0.049). CONCLUSIONS/INTERPRETATION: Following bedtime injection of NPH insulin or of the analogues insulin detemir or insulin glargine, fasting glucose <7 mmol/l was achieved in the morning, without subsequent hypoglycaemia when participants continued to fast during the day.