The concept of adaptation has gained central importance in research on chronic disease. The article reviews recent developments in the major theoretical concepts, coping, defense and social support. A schema for classification is introduced distinguishing coping and defense processes at the individual (cognitive-emotional and behavioral), interpersonal and institutional levels. Some often neglected aspects of the evaluation (concerning temporal orientation, level, areas and perspective of rater) are pointed out. Underlying methodological aspects are briefly reviewed. Applying conceptual demands of theories of adaptation to research on chronic disease shows major research deficits, especially a lack of accepted definitions of adjustment, a preference for static, one-dimensional and cross-sectional research and a lack of adequate assessment procedures. Desiderata for future research are suggested.