This study addressed whether the educational impact of a zoo visit can be enhanced through the provision of appropriate instructional supports such as preparatory trainings or orientations. One important function of the educational process, in contrast to providing direct information or skill development, is to make the learner more sensitive to the learning environment by developing motivation and increasing skills in attention and/or selective perception. This is particularly significant when dealing with experiential education settings such as zoos, because those settings tend to be unstructured and the learner is more on his or her own. The subjects, Extension 4-H agents, were either presented an orientation lecture with slides, or given a packet of orientation reading materials. The two groups visited the San Diego Zoo in November 1987 as part of the annual meeting of the National Association of Extension 4-H Agents. Both of these groups were tested against a control group. This study demonstrated that orientation sessions can serve to boost the educational effectiveness of zoos, at least in the area of knowledge gain. The orientation did not increase the strength of attitudes and values related to zoos. (MVL)