The authors conducted an evaluation of visitor knowledge and conservation attitudes toward African apes at Chicago's Lincoln Park Zoo. Using S. R. Kellert's and J. Dunlap's (1989) analysis of zoo visitor knowledge and attitudes as a model, they modified and administered a survey to 1,000 visitors to the ape facility. On average, visitors correctly answered 60% of knowledge questions, performed better on exit than entrance surveys, and correctly answered more chimpanzee- than gorilla-oriented questions. Older and more educated people performed better on knowledge questions than did younger and less educated people. The predominant attitude toward African apes was naturalistic and the least characteristic attitude was utilitarian. Attitudes toward chimpanzees differed from attitudes toward gorillas. There was no difference between entrance and exit surveys on attitudes, but repeat visitors exhibited more ecoscientistic attitudes than did first-time visitors. Higher education levels, and better performance on knowledge questions, were associated with increased knowledge of ape behavior and lower negativistic and dominionistic attitudes toward apes. These findings underscore the importance of both formal and informal educational experiences in improving knowledge of and attitudes toward African apes.