Uniform standards for the recording and scoring of respiratory events during sleep are lacking in Europe, although many centres follow the published recommendations of the American Academy of Sleep Medicine. The aim of this study was to assess the practice for the diagnosis of sleep-disordered breathing throughout Europe. A specially developed questionnaire was sent to representatives of the 31 national sleep societies in the Assembly of National Sleep Societies of the European Sleep Research Society, and a total of 29 countries completed the questionnaire. Polysomnography was considered the primary diagnostic method for sleep apnea diagnosis in 10 (34.5%), whereas polygraphy was used primarily in six (20.7%) European countries. In the remaining 13 countries (44.8%), no preferred methodology was used. Fifteen countries (51.7%) had developed some type of national uniform standards, but these standards varied significantly in terms of scoring criteria, device specifications and quality assurance procedures between countries. Only five countries (17.2%) had published these standards. Most respondents supported the development of uniform recording and scoring criteria for Europe, which might be based partly on the existing American Academy of Sleep Medicine rules, but also take into account differences in European practice when compared to North America. This survey highlights the current varying approaches to the assessment of patients with sleep-disordered breathing throughout Europe and supports the need for the development of practice parameters in the assessment of such patients that would be suited to European clinical practice.