Once a pristine recreational center and a productive fishery that supplied New York City markets with fresh fish, Onondaga Lake is now considered one of the most badly degraded bodies of water in the entire world (Sage 1993). The Onondaga Lake Management Conference was established to develop a comprehensive restoration, conservation, and management plan for Onondaga Lake that recommends priority corrective actions and a compliance schedule for cleanup of the lake. Biological assessment of the lake has been infrequent and concentrated on a few biological groups. This study either updates or establishes baseline characteristics for the following biological components of the Onondaga Lake ecosystem: phytoplankton, zooplankton, ichthyoplankton and macrobenthos