The objective of this investigation was to assess the association between the presence of sleep disordered breathing (SDB) and daytime sleepiness, body mass index, hospitalisation, and survival. To this end, a prospective longitudinal study was conducted in the elderly population consisting of 80 patients of either sex over the age of 65 years admitted to a city hospital in Germany without any history of SDB. All patients met the following exclusion criteria: age <65 yr, heart failure, and chronic obstructive lung disease. Baseline anthropometric and cardiorespiratory (one-night portable polygraphic recording) data, and a standardized sleep and sleepiness-questionnaires (Epworth Sleepiness Scale, ESS) were obtained in 1999. A second screening was conducted in 2003. Thirty one women and 34 men completed the follow-up after 3 years. These patients were divided into two subgroups: (i) no clinically relevant SDB and (ii) SDB (apnea-hypopnea index, AHI, >or=5 plus excessive day time sleepiness, ESS, >9). Six men and 3 women fulfilled the criteria of SDB. Thirty three percent of patients with SDB and 20% of patients without SDB died during the follow-up period. Duration of hospital stay was 35 days for the SDB patients and 20 days for patients without it. Body weight and sleepiness did not change significant over the 3-year period between the two cohorts. We conclude that the presence of SDB was associated with a 1.5-fold higher mortality and longer hospital stay in elderly patients over a period of 3 years even in persons without previous history of SDB. Daytime sleepiness was a better predictor than AHI or BMI for death.