Because regular insulin does not lower blood glucose immediately after injection many physicians recommend an injection-meal interval (IMI). By asking patients to inject well before beginning a meal, these physicians hope to compensate for the lag time between the injection of insulin and its onset of action. The aim of our study was to find out what physicians recommend to their patients with respect to the IMI, when prescribing intensive insulin therapy. A total of 58 diabetologists were surveyed by means of a structured questionnaire. A fixed IMI of 15 (0-30) min [median (range)] was recommended by 29% of the 58 diabetologists, and a flexible IMI was recommended by 71%. The minimal interval for the suggested flexible IMI was 0 min and the maximal interval 45 min (median 23 min). We compared these results with findings of 192 patients with Type 1 diabetes from a population based study. In this study patients were asked by questionnaire about their daily life handling of the IMI. Among the group of 134 patients reporting use of a flexible IMI, 62% used an IMI of < or = 15 min, 16% one of 20-25 min, and 21% one of > or = 30 min. There were 12 patients using a flexible IMI who adapted it so frequently that they could not state a typical interval. A total of 58 patients (30%) used a fixed IMI (67% used an IMI of < or = 15 min, 7% one of 20-25 min, 26% one of > or = 30 min). Our surveys show that diabetologists advocating intensive insulin therapy usually recommend an IMI shorter than 30 min. The majority of patients (75%) with Type 1 diabetes use an IMI of < 30 min in daily life.