In 1998 zopiclone had a 42% share of the prescribed hypnotic drug market in Norway. The National Institute of Forensic Toxicology analyses all blood samples from suspected drugged drivers. The rise in zopiclone prescription was partly reflected in an increase in the number of drivers with zopiclone detected in the blood. We looked closer at the test results from 101 drivers with zopiclone detected in their blood in the January 1994 to April 1999 period. 60% had blood concentrations of zopiclone above the concentration observed after intake of therapeutic doses; 80% had higher blood concentrations than those expected 8 hours after intake of therapeutic doses. The majority of the drivers also tested positive for illegal drugs, prescription drugs with abuse potential, or alcohol. This indicates that zopiclone is misused or abused. Therefore the same caution should be applied when prescribing zopiclone as is applied when prescribing e.g. benzodiazepines.