Previous studies of tournament-related impacts on black bass (Micropterus spp.) have concluded that live-release tournaments have minor effects on fisheries. Prompted by a decline in numbers of largemouth bass (M. salmoides) ≥ 458 mm total length (TL) and a high ratio of tournament weighed-in fish to harvested fish by non-tournament anglers, we assessed the impacts of tournament angling at Amon G. Carter Reservoir, Texas (623 ha). In 2007, we tagged 786 largemouth bass and estimated fishing mortality separately for tournament and non-tournament anglers. Instantaneous total fishing mortality was estimated to be 0.14, with tournament mortality responsible for 65% of all angling-caused fish deaths. Our simulation model predicted abundance of largemouth bass ≥ 356 mm and ≥ 457 mm would increase by 6% and 9%, respectively, under a 50% reduction in tournament catch and by 13% and 20%, respectively, if there was no retention of tournament fish. Tournament angling impact on total fishing mortality and largemouth bass population abundance was greater at Amon G. Carter Reservoir than at previously investigated reservoirs.