AIM OF THE STUDY: To evaluate if perennial non-infectious rhinitis is associated with sleep disturbances in asthma. MATERIALS AND METHODS: This is a questionnaire based study in a random population sample from Denmark, Estonia, Iceland, Norway and Sweden aged 30-54yr. A total of 1127 individuals reporting asthma from an original random population sample of 16,191 were analysed regarding their quality of sleep in relation to perennial non-infectious rhinitis. Perennial non-infectious rhinitis was defined as having nasal symptoms such as nasal blockage and secretion in the absence of common cold, always. Asthma was defined as both ever having had asthma and having physician diagnosed asthma. Odds ratios (OR) for difficulties inducing sleep, difficulties maintaining sleep, early morning awakenings and daytime sleepiness were calculated in a multiple logistic regression controlling for other risk factors for sleep disturbances such as snoring, wheeze, obesity and smoking. RESULTS: The response rate was 74%. A total of 189 (17%) of the subjects with asthma reported perennial non-infectious rhinitis. Perennial non-infectious rhinitis was associated with an increased OR for difficulties maintaining sleep (1.6 (95% confidence interval (CI) 1.1-2.3)), early morning awakenings (1.5 (95% CI 1.1-2.2)) and daytime sleepiness (1.8 (95% CI 1.2-2.9)). The result show that perennial non-infectious rhinitis is an independant risk factor for sleep disturbances in asthma.