Association of snoring and cognitive function was studied in 46 habitually snoring men ages 41-52 years, and 60 occasionally or never-snoring control male subjects of the same age group. Sleep recordings with monitoring of apneas and hypopneas were made with the static-charge sensitive bed method. Blood oxygen saturation was measured with an oximeter and the snoring sounds were recorded with a microphone after clinical and neuropsychological assessment. A questionnaire with items on excessive daytime somnolence (EDS), sleep, and snoring quality was also used. EDS (as measured by items on the questionnaire) associated with tests requiring concentration, memory retention, and verbal and spatial skills in the habitual snorers group. The number of oxygen desaturation episodes exceeding 4% associated with defective delayed Recall of Logical Stories of the Wechsler Memory Scale and with spatial orientation (Clock test) in the habitual snorers' group even after adjusting for age and obesity.