This study investigates the association between sleep-disordered breathing (SDB) and mortality in a large community sample of adults aged 40 years or older. The Sleep Heart Health Study, a prospective cohort study, examined 6,441 participants, assessing SDB severity using the apnea-hypopnea index (AHI). The average follow-up period was 8.2 years, during which 1,047 participants died. The results showed that compared to those without SDB (AHI <5 events/h), those with mild, moderate, and severe SDB had hazard ratios for all-cause mortality of 0.93, 1.17, and 1.46, respectively. Stratified analyses by sex and age revealed that the increased risk of death associated with severe SDB was statistically significant in men aged 40–70 years (hazard ratio: 2.09). Measures of sleep-related intermittent hypoxemia, but not sleep fragmentation, were independently associated with all-cause mortality. Coronary artery disease-related mortality showed a similar pattern of association with SDB. The study concludes that SDB is associated with all-cause mortality, particularly due to coronary artery disease, in men aged 40–70 years with severe SDB.This study investigates the association between sleep-disordered breathing (SDB) and mortality in a large community sample of adults aged 40 years or older. The Sleep Heart Health Study, a prospective cohort study, examined 6,441 participants, assessing SDB severity using the apnea-hypopnea index (AHI). The average follow-up period was 8.2 years, during which 1,047 participants died. The results showed that compared to those without SDB (AHI <5 events/h), those with mild, moderate, and severe SDB had hazard ratios for all-cause mortality of 0.93, 1.17, and 1.46, respectively. Stratified analyses by sex and age revealed that the increased risk of death associated with severe SDB was statistically significant in men aged 40–70 years (hazard ratio: 2.09). Measures of sleep-related intermittent hypoxemia, but not sleep fragmentation, were independently associated with all-cause mortality. Coronary artery disease-related mortality showed a similar pattern of association with SDB. The study concludes that SDB is associated with all-cause mortality, particularly due to coronary artery disease, in men aged 40–70 years with severe SDB.