Knowledge of conditions associated with an increased prevalence of obstructive sleep apnoea (OSA) may help to identify patients with OSA and might give some insight into the pathogenesis of OSA and its sequelae. A number of earlier, smaller studies hinted at an association between diabetic cardiovascular autonomic neuropathy (AN) and OSA. The present study was, therefore, conducted with the aim of establishing the prevalence of OSA in diabetics with AN and of determining whether OSA is more prevalent in diabetics with AN, than in those without. We studied two groups of diabetic patients: 23 with and 25 without AN. All patients were evaluated for possible OSA (apnoea/hypopnoea index ± 10) using initial ambulatory screening followed by polysomnography. Six patients with AN (26%) were found to have OSA, but none of the patients without AN met the diagnostic criteria (p < 0.01). When the patients with OSA were compared to those without, no differences were found in terms of age, sex, body mass index or diabetes type or duration. In conclusion, about one in four diabetic patients with autonomic neuropathy suffers from OSA. Thus, obstructive sleep apnoea is more prevalent in diabetic patients with autonomic neuropathy, than in those without.