May 1992 amendments to the pulp and paper effluent regulations under the Fisheries Act required mills to conduct an environmental effects monitoring program. One required component of this program was that mills conduct sublethal toxicity tests to measure the inhibition of fish early life stage development, invertebrate reproduction, and plant toxicity by a sample of mill effluent. For cycle 1 of the tests, the mills were required to conduct four sets of tests within a one-year period; for cycle 2, they are required to conduct two sets of tests each year over a three year period. This report compares the interim results of cycle 2 tests with the results from the cycle 1 tests completed by pulp and paper mills in the Atlantic region. Test data are presented for mills discharging to both freshwater and marine environments.