Abstract This study investigated the relationship of daytime sleepiness and performance on a vigilance test in a sample of 10 healthy men and 13 women in their 80s (mean age 83.0 ± 3.1 years) and 18 men and 12 women in their 20s (25.0 ± 3.1). We hypothesized that “successfully” aged healthy individuals would have more daytime sleepiness with differentially greater decrements in performance than a younger comparison group. Daytime sleepiness was measured physiologically by the Multiple Sleep Latency Test (MSLT) and through self-report by the Stanford Sleepiness Scale (SSS). Morning and evening performance was measured with the Mackworth Clock Test of vigilance. The major findings were the absence of correlation between either MSLT or SSS daytime sleepiness with performance measures, no difference in daytime sleepiness between the old and young groups and performance decrements among the healthy elderly on all parameters. Results suggest that the modest decrements in performance among the elderly cannot be attributed to daytime sleepiness.