Increasing incidents of disorders such as obesity/diabetes/metabolic syndrome, reproductive dysfunction, and neuro-developmental abnormalities in some human populations have raised concern that disruption of key endocrine-signaling pathways by exposure to environmental chemicals may be involved. This Detailed Review Paper describes some endocrine pathways that have been shown to be susceptible to environmental endocrine disruption and whose disruption could contribute to increasing incidents of some disorders in humans and wildlife populations.