Back ground: Leather production includes many operations with different exposures, which can be harmful for the health of the workers. Aim: The study aimed to evaluate the effect of occupational health program on prevention of occupational health hazards among workers at Leather Tanning Factory. Methods: Quasi-experimental (pre/post-test) design was utilized in this study. The study was conducted at Leather Tanning Factory, Industrial Zone, Queisna City; Menoufia Governorate, Egypt with a systematic random sample was used. The total sample of the study was included 200 workers. Tools: I): A structured interviewing questionnaire which consisted of three parts to assess workers' socio-demographic characteristics, health problems which the workers suffer from at last six months and workers` knowledge about occupational health hazards II): Observational checklist to assess the environmental work setting and workers practices regarding prevention of occupational health hazards. Results: 37% of the studied workers aged between 30-