Nasal problems are often reported during the treatment of obstructive sleep apnoea syndrome (OSAS) with nasal continuous positive airway pressure (nCPAP) and may jeopardize the use of nCPAP. This retrospective study evaluated the frequency of nasopharyngeal symptoms in OSAS patients before and during nCPAP treatment. A questionnaire was sent to all patients (n = 194) with OSAS for whom nCPAP had been prescribed during the years 1990-1995 at the authors' hospital, enquiring about nasopharyngeal symptoms both before and during treatment and nCPAP use. The study population consisted of the 151 patients [128 men and 23 women, median (range) age 54 (31-76) years and body-mass index 34 (17-54) kg/m2] who responded to the questionnaire. Seventy-one percent of patients were still using nCPAP after a median treatment duration of 30 months. The most commonly reported nasopharyngeal symptoms were nasal stuffiness, which was reported by 46% of patients before nCPAP and by 37% during nCPAP, dry nose (39% before and 46% during nCPAP), sneezing (36% and 35%) and rhinorrhoea (21% and 27%). The frequency of nasopharyngeal symptoms did not change with nCPAP treatment. The frequency of nasopharyngeal symptoms before and during nCPAP treatment was similar in those patients who discontinued the treatment (n = 44, 29%) compared with those who continued with nCPAP (n = 107, 71%). Skin problems caused by the mask (50%), airleak from mouth (44%), difficulty in exhaling (29%) and a sensation of suffocation (26%) were also problems associated with nCPAP treatment. Nasopharyngeal symptoms were common in patients with OSAS before nCPAP was started. There was no significant change in the frequency of these symptoms during nCPAP treatment. Nasopharyngeal symptoms did not seem to affect treatment continuation.