It is tried with the concept of environmental competence (NC) to integrate different paradigms in the field of humae ecology. NC is an interactive construct which is related to individuals in specific environments and not to individuals per so. At least six characteristics of individuals and environments are essential for EC Degree of stimulation - readability of situational components - avail ability of behavioral alternatives - predictability of environmental changes cognitive - and behavioral competence - interpersonal consensus of defining the situation. The necessity of EC for designing for the elderly and concrete architectural and organisational cuieqnences are demonstrated.