Programmed cell death or apoptosis is an evolutionarily conserved process which is essential for the maintenance of tissue homeostasis. Recent studies have indicated a role for apoptosis in a variety of human diseases. Hence, dysregulation of apoptosis has been implicated in, for instance, systemic and organ-specific autoimmune disease, acquired immune deficiency syndrome, neurodegenerative disorders, atherosclerosis and cancer. This presentation serves as an overview of pathological conditions, which are associated with defective or inadvertent apoptosis, with examples of disorders in which putative apoptosis defects have been elucidated at the molecular level. A critical assessment of apoptosis as a target for therapeutic intervention is also provided. Copyright (C) 2001 S. Karger AG, Basel.