Ages of 76 known-age white-tailed deer (Odocoileus virginianus) were estimated by tooth wear and replacement (TWR) and by incisor cementum annuli (CA) determination. TWR and CA methods gave similar results (75% and 71% correct, respectively). However, accuracy was dependent on deer age, with TWR being more accurate than CA in age classes <3.5 years and CA being more accurate in age classes >3.5 years. Accuracy of 55 southeastern United States biologists in estimating age of 98 known-age deer jaws also was determined. Results indicated biologists were well-skilled in the TWR technique but generally underestimated actual age class >3.5 years. Using their mode response (N = 98), biologists correctly determined age for 71.4% of the jaws; however, when using their estimates given for all jaws (N = 5,390), 62.6% were aged correctly.