Thirty-three anglers participated in the 1992 eastern Ontario cooperative muskellunge angler diary program. These anglers reported exerting a total of 3,490.75 angler hours fishing effort on sixteen different waterbodies to catch a total of 205 muskellunge. Angling activity and muskellunge catches were relatively constant throughout the open water (June-November) season with the exception of October when fishing effort and catches were highest. Six large river systems (Madawaska, Moira, Ottawa, Petawawa, Rideau and St. Lawrence) accounted for 88.4% of the angling effort and 71.2% of the muskellunge catch. The proportion of legal-sized muskellunge in the catch varied considerably among different waterbodies but averaged 52.2% for all waters combined. All but three fish from the reported muskellunge catch were released. On waters receiving a minimum of one hundred hours of angler effort, muskellunge catch-per-unit-of-effort values ranged from 0.018 to0.214 fish per angler hour. The 1992 cooperative program was the fourth consecutive year that muskellunge data has been collected and summarized. This program represents the only continuous source of information on the eastern Ontario muskellunge fishery. It is recommended that a similar project be implemented again in 1993.