Characteristics of the self-definition were investigated in a heteroge
neous sample of N = 516 participants of the Berlin Aging Study (BASE,
age-range: 70-103 years, M = 84,9). The investigation of the self-defi
nitions of older adults provides insights into the salient life themes
and processes of their <<person-environment interaction>>. An analysi
s of the content of the self-definition revealed that old and very old
individuals defined themselves as active and present-oriented, At the
same time the content of their self-definitions reflected an inward o
rientation and a central theme of life-review. As expected, health pro
ved to be one of the most important life issues. Although even the ver
y old produced more positive than negative evaluations in their self-d
efinition, the ratio of positive to negative evaluations was less favo
rable for the 85 to 103 year olds when compared to the 70 to 85 year o
lds. The multifacetness of the self-definition appears to decrease in
very old age as a function of health-related constraints. Positive emo
tional well-being was associated with having more self-defining domain
s and a richer description of these domains. Multifacetness of the sel
f-definition, however, did not buffer against the negative effect of d
iminished functional capacity on positive emotional well-being.