The results of the effluent and environmental monitoring programs at the three Knolls Atomic Power Laboratory (KAPL) Sites are summarized and assessed in this report. Operations at the Knolls Site, Niskayuna, New York and the Kesselring Site, West Milton, New York and site closure activities at the S1C Site, Windsor, Connecticut, continued to have no adverse effect on human health and the quality of the environment during calendar year 2000. The effluent and environmental monitoring programs conducted by KAPL are designed to determine the effectiveness of treatment and control methods, to provide measurement of the concentrations in effluents for comparison with applicable standards, and to assess resultant concentrations in the environment. The monitoring programs include analyses of samples of liquid and gaseous effluents for chemical constituents and radioactivity as well as monitoring of environmental air, water, sediment, and fish. Radiation measurements are also made around the perimeter of each Site and at off-site background locations. Monitoring programs at the S1C Site were reduced in scope during calendar year 2000 due to completion of site dismantlement activities during 1999.