Age and gender-related differences in blood- and breath-alcohol concentrat 51101Aions were investigated among drinking drivers apprehended in Sweden between 1994 and 1998. During this 5-year period the number of suspects decreased appreciably from 21000 to 14600. The concentration of alcohol was below the statutory limits (0.2 mg/g blood or 0.1 mg/L breath) in about 20 per cent of suspects after making an allowance for uncertainty. About 11 per cent of all drunk drivers were women. The mean concentration of alcohol was about 50 per cent higher for those who gave blood samples compared with evidential breath tests regardless of gender. The median age of drunk drivers tended to be higher for women then for men but the average alcohol concentration was higher for men than for women. The average alcohol concentration for all groups regardless of gender increased between 1995 and 1998. The age distribution changed over the period studied with the proportion of drivers between 20-29 years decreasing and those aged 50 and over increasing. This trend was consistent in all subgroups so the average and median ages of drunk drivers in Sweden increased. This survey shows that drinking drivers in Sweden are getting fewer, older and drunker.