Background: Skin cancer is one of the most common cancers that is mostly caused by ultraviolet radiation. The aim of this study was to investigate the factors affecting skin cancer preventive behaviors in medical sciences students based on the extended parallel process model that is responsible for the future health of the community. Methods: This descriptive cross-sectional study was carried out among 150 students who were selected by the simple random sampling method in Yazd in 2017. The data were collected by translating the questionnaire based on the extended parallel process model. The data were analyzed by SPSS-18 software and descriptive tests and non-parametric Mann-Whitney, Kruskal-Wallis tests, Spearman correlation and linear regression at a significance level of 0.05.  Results: The mean age of participants was 22.01 ± 5.24, more than half of whom (57.3%) used sunscreen as a self-protective behavior against the sunlight. The perceived severity construct had the highest score among the constructs (79.53) and preventive behaviors score (61.7). Among the demographic variables, gender had a significant statistical difference with the constructs of fear and behavioral intention, and preventive behaviors and economic status variable in the perceived response efficacy construct. Among the model constructs, the behavioral intention was the strongest behavioral predictor of skin cancer prevention (p< 0.000,β =0.589). Conclusion: In view of the findings, it seems necessary to increase protective behaviors against sunlight and skin cancer prevention by removing existing barriers including cultural issues. Also, recurrent training can be effective in promoting behavioral intention of student in preventing skin cancer.