Workplace drug testing is less common in Norway than in many other countries. During the period from 2000-2006, 13469 urine or blood samples from employees in the offshore industry, shipping companies and aviation industry were submitted to the Norwegian Institute of Public Health for drug testing. The samples were analysed for benzodiazepines, illicit drugs, muscle relaxants with sedating properties, opioids and z-hypnotics. In total, 2.9% of the samples were positive for one or more substances. During the study period the prevalence decreased for morphine (from 1.9% to 1.1%) and increased for amphetamine (from 0.04% to 0.6%), clonazepam (from 0% to 0.1%), methamphetamine (from 0.04% to 0.6%), nitrazepam (from 0% to 0.4%) and oxazepam (from 0.5% to 1.3%) (p<0.05). There was no significant change in prevalence for the other substances included in the analytical programme. Illicit drugs were significantly associated with lower age (OR: 0.93, p<0.05). This study found low prevalence of drugs among employees in companies with workplace drug testing programmes in Norway.