Sudden death and sleeping history among Finnish men. An autopsy was performed in 460 consecutive cases of sudden death among 35- to 76-year-old men. The closest cohabiting individual known to each decreased subject was interviewed. Snoring history was obtained in 321 of the 371 interviews. In 86 cases there was a history of 'habitual' (almost always or always) snoring, and 88 men snored 'often'. The mean age of subjects was 55.4 years. The mean body mass index (BMI) was 26.3 kg m-2. Among the obese snorers (n = 82), apnoeas had been observed 'occasionally', 'often', or 'habitually' in 49 cases. Death was classified as cardiovascular in 186 (40.4%) cases. Cardiovascular cause of death was more common among those who snored habitually or often than among those who snored occasionally or never (P less than 0.05). 'Habitual' snorers died more often while sleeping (P less than 0.05). Habitual snoring was found to be a risk factor for morning death (P less than 0.01). The possibility of obstructive sleep apnoea as a cause of sudden death should at least be considered if the decreased is known to have been a habitual snorer. 