The assessment and utilization of strengths, competences and resources of a person draws more and more attention to itself, supplementing the psychopathological oriented assessment in psychotherapy. This development has recently been pushed through the endeavour of the Positive Psychology. Geropsychotherapy, in particular, can profit from a resource orientation. This article pursues two aims: First, diagnostic instruments measuring various resources are described. Second, empirical findings of positive consequences of these resources in older age are summarized. Considered are emotional resources (positive affect, life satisfaction, self-esteem), motivational resources (locus of control, self-efficacy, dispositional optimism, optimistic attributional style, hope, intrinsic life goals), volitional resources (action orientation, self-regulation and self-control, attention regulation, emotion regulation), interpersonal resources (attachment, altruism, social responsibility, forgiveness, humour) and social resources (social network, social support, partner relationship). The need of assessment of resources in psychotherapy is discussed, several changes on the DSM-IV are proposed, and conclusions for planned research are drawn.