Background: Welding manufacturing poses a variety of chemical, physical, biological, psychological and ergonomic risks to the health of workers. The aim of the study was to assess the occupational health hazards among workers of welding factories. Research design: A descriptive research design was utilized. Setting: This study was carried out at Elegect Factory, and Electromica Factory in Mostorod. Sampling: Convenience sample of workers who worked in the previously mentioned settings: That included 200 workers. Tool: One tool was used for data collection that consisted of the following parts; A) socio- demographic characteristics, B) Occupational hazards and health problems facing welding workers in the last six months, and C) welding workers' knowledge, and reported practice regarding dealing with emergency situations as first aid. Results: 40.5% of studied workers was in between 20<30 years and 48, 5 % had basic education, 51.5% of them live in Urban area. 49% of the studied workers had 5<10 years of experience. 44%, 23.5%, 26.5%, 46%, 37% and18.5 % of the studied workers had nasal irritation due to rising gases, nausea, excessive tearing, and ear ache, skin burns, and numbness in the limbs respectively regarding their occupational health problems in the first six months of work. Conclusion: More than half of the studied workers had poor total knowledge level about occupational hazards related welding exposure, and less than ten percent of them had good total knowledge level  about occupational hazards related welding exposure. Less than three quarters of the studied workers had satisfactory total practices regarding precaution in welding factories, there was positive correlation between total knowledge level and their total practices level of the studied workers regarding occupational health hazards in welding factories. Recommendation: Develop training program for workers at welding factories to improve their knowledge and practices regarding occupational health hazards and regular periodic checkup for all workers for early detection of any health problems and health needs.