At present, sexually transmitted disease (STD) and AIDS are important public health problem of Thailand, especially when considering on age group, occupation of the risk group, it was found that the recruit was one of risk group. Therefore the objective of this research was to study the effectiveness of health education program on STD and AIDS preventive behavior among the navy recruits in Songkhla Province. The researcher modified Becher Mimans Health Belive Model and used its principles in construction the contents of the Health education program. the program also applied Social Learning Theory to promote a correct STD and AIDS preventive behavior among the recruits. The study was a quasi-experimental research. The final sample selection used simple random sampling. The sample wer divided in to 2 group : experimental group and comparison group. By the end of the last session of experiments. the sample of each group remained only 45. The instrument for data collection was the questionnaire developed by the researcher. Data were filled out by the recruits. Health education program started by the researcher gave a lecture at the first session to the experimental group. Later session group discussion was conducted. Videotape display, exhibition had been shown to the recruits. Condoms were provided free of charge to everyone where as the comparison group did not recive any health education massage. Data collection was administered 3 times through out the experiment. Data were analysed in percentage, arithamatic means, standard deviation. Statistics for testing difference were Students t-test, Paired Sample t-test, 2-test. Pearsons Product Moment Correlation Coefficient was employed for testion of relationship. The main findings were as follows: 1. The mean scores on knowledge of the experimental group after giving health education program (HEP) was significantly higher than before giving HEP and Higher than the comparison group. 2. The mean socores on perception of risk, severity of disease of the experimental group and the comparison group was not different at the end of the first and the second sessions. It was not also different when compaired between prior to experiment at the end of the first and second sessions. 3. The mean socres on perception of practicing of the experimental group was significantly higher than the comparison group at the end of the first and the second sessions. After expeiment, it was also significantly higher than after the end of the first and the second session. 4. There was norelationship between knowledge, perception of disease and practice in prevention of STD and AIDS. 5. Proportion of condom usage in STD and AIDS prevention after HEP, the experimental group was significantly higher than the comparison group. In conclusion, the research result, indicated that HWP was effective. It Positively affected preventive behavior on STD and AIDS among the recruits. The researcher would like to recommend that HEP should be provided for all group of soldiers. Teh program might well-organized in contents and process. It will be started by lecturing and slide, videotape, leaflets, poster, exhebition, sticker are fully utilized. Condoms have to be provided free of charge.