We investigated the prevalence and treatment of patients with chronic insomnia presenting to Swiss primary care physicians (PCPs) part of "Sentinella", a nationwide practice-based research network. Each PCP consecutively asked 40 patients if they had sleep complaints, documented frequency, duration, comorbidities, and reported ongoing treatment. We analysed data of 63% (83/132) of the PCPs invited. The PCPs asked 76% (2,432/3,216) of included patients about their sleep (51% female); 31% (761/2,432) of these had had insomnia symptoms; 36% (875/2,432) had current insomnia symptoms; 11% (269/2,432) met the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria for chronic insomnia (61% female). In all, 75% (201/269) of patients with chronic insomnia had comorbidities, with 49% (99/201) reporting depression. Chronic insomnia was treated in 78% (209/269); 70% (188/268) took medication, 38% (102/268) benzodiazepines or benzodiazepine receptor agonists, 32% (86/268) took antidepressants. Only 1% (three of 268) had been treated with cognitive behavioural therapy for insomnia (CBT-I). A third of patients presenting for a non-urgent visit in Swiss primary care reported insomnia symptoms and 11% met the DSM-5 criteria for chronic insomnia. Hypnotics were the most common treatment, but almost no patients received first-line CBT-I. Reducing the burden of insomnia depends on disseminating knowledge about and access to CBT-I, and encouraging PCPs to discuss it with and offer it as a first-line treatment to patients with chronic insomnia.