The purpose of this study was to evaluate the effectiveness of health education through exhibition of posters on the knowledge and perception of the students of the Institute of Technology in Ratchaburi Province, on STDs, AIDS, Family Planning and Reproductive Physiology. These students were chosen to be educated on the above subjects as not only to acquisition of and hence transmission of STDs and AIDS but also to unwanted pregnancies. A quasi-experimental, before-after design was used for the study with a structured questionnaire in Thai language, which was based on the twelve posters. The same questionnaire was used for both the pre and post test. The was followed by exhibition of posters for two weeks, after which a post test was taken. The post test was followed by a focus group discussion. The results showed that the students had a high level of knowledge and perception on the topics exhibited at the pre test, which was due to the effect of other media books, magazines and through the health _ in their high school. The post test result showed a significant increase in the level of knowledge and perception. The present exhibition of posters has resulted in this change by refreshing the knowledge of these students who claimed to have already received informations regarding these topics. The focus group discussion that the students were receptive to this mode of health education were colorful and had I limited but specially. It is recommended that clorful posters with a lot of pictures but with limited, easily undersandable messages should be made accessible to all the youths to make them aware of the diseases and unwanted pregnancies that is acquired through risky behavior and what are the preventive measures they can take.