['To evaluate the effect of short-term training of general practitioners (GPs) on their diagnosis and treatment of chronic insomnia.', 'A three-step randomized control group design was used: After baseline evaluation (T1) a group of 9 GPs underwent a training of half a day, while 7 GPs served as a control group. The diagnostic and therapeutic handling of insomnia patients was reevaluated under obligatory use of a structured diagnostic questionnaire (T2) and under optional use of it (T3).', 'From 16 general practices, 4,754 patients were included. The frequency rate of insomnia was 19.3 %. The lowest diagnostic and treatment rate was found for insomnia patients without comorbidity (15 % at T1). Systematic non-pharmacological treatment was not offered by the GPs. At T2 the diagnosis rate increased significantly from 37.9 % (T1) to 71.5 % (T2, p = 0.038). It fell back to lower levels at T3 but remained better than at T1. At T3 non-pharmacological treatments and referral to a sleep expert were advised more often.'] Does short-term training increase diagnostic and treatment rate for insomnia in general practice?