ABSTRACT. In the elderly, depression appearing with medical illness seems to be the rule rather than the exception and leads to significant comorbidity. Effective diagnosis and treatment is therefore essential. Comorbidity invariably leads to conceptual and diagnostic dilemmas, since depression may be both a cause and a consequence of medical illness. Thus, the pathways through which depression and medical illness interact are considered. Treatment issues pertinent to depression comorbid with medical illness are presented, and the utility of reciprocal models that can help formulate treatment plans is discussed. Overall, the need for interventions that improve quality of life for individuals with depression and chronic health problems is highlighted.