Background and purpose: To carry out an observational epidemiological survey (Studio Morfeo), to determine: (1) the frequency of insomnia in a large Italian population presenting directly to the general physician (GP); (2) the impact of insomnia on the quality of life, on the use of health-care resources and on co-morbidity. Patients and methods: The study was accomplished by GPs, trained by sleep specialists accredited by the Italian Association of Sleep Medicine. Only patients spontaneously presenting to their GP for medical problems were surveyed. Each GP was asked to enroll at least five patients across a routine week of medical activity including both morning and afternoon clinics. The first patient of each weekday was recruited after obtaining written consent. According to the responses to the sleep-related questions, patients were classified into three categories: (1) no insomnia, (2) level I insomnia with absence of day-time dysfunction and (3) level 2 insomnia with presence of day-time dysfunction. Results: A total of 3284 patients were enrolled by 738 GPs in this Italian survey. Insomnia was reported by 64% of all interviewed patients, with 20% classified as level 1 and 44% as level 2. Logistic analysis indicated that depression (odds ratio, 2.70), involvement of >1 organ systems (odds ratio, 1.24). female gender (odds ratio, 1.19), unemployment (odds ratio, 1.18), low education (odds ratio, 1.18) and increasing age (odds ratio, 1.02) were the major risk factors for insomnia. Conclusions: Our findings indicate that insomnia is a frequent disturbance in the Italian primary care population, is associated with high risk of co-morbid conditions, and results in increased use of health-care resources.