The rearrest rates among Norwegian drugged (n=1102) and a group of drunken drivers (n=850) (BAC: 0.16-0.19%) apprehended during 1992, were 57% (n=629) and 28% (n=238), respectively, when followed prospectively for 7 years. The most important risk factors for recidivism among drugged drivers were previous arrests for drugged or drunken driving (rearrest rate among previous arrests: 73%, no previous arrest: 42%), multi-drug detection at selection (multi-drug: 62%, single drug: 41%), sex (male: 61%, female: 35%) and age (below 36 years: 60%, 36 years and older: 44%). Most of the recidivist drugged drivers were rearrested during the year of selection (21%), followed by 13, 7 and 6%, retrospectively, during the following years. When followed both retrospectively and prospectively for a period extending from 1984 to 1998, 71% (n=779) and 40% (n=344) of the selected drugged and drunken drivers, respectively, were arrested two or more times.