Midazolam, a new water-soluble benzodiazepine, was compared with thiopentone as an induction agent prior to inhalational anaesthesia. Induction time, cardiovascular response and venous sequelae were studied in 100 healthy in-patients randomly divided into two groups. Midazolam proved to be a good alternative to thiopentone, the longer induction time being compensated by a lower incidence and duration of apnoea.