This paper deals with the relationship between health status and health perception in very advanced age. We examine how older people assess their own health and at the same time we investigate the equivalence between their health status and the perception they have of it. Based on quantitative and qualitative data collected under the {Swiss Interdisciplinary Longitudinal Study on the Oldest Old} (SWILSOO), this analysis confirms that, while both health status and self-rated health deteriorate in very old age, people aged 80 and over tend to underestimate the decline. We show that the widening gap between perceived and objective health status can be accounted for by mechanisms of comparison. The qualitative data point to the use of various forms of comparison which allow older people to maintain a relatively favourable perception of their own health — and therefore of themselves — until a very advanced age.