Background & Objectives: Musculoskeletal disorders and premature tiredness caused by work are arisen from incompatible individual work capacity and job demands. According to the statistics provided by World Health Organization (WHO), prevalence of musculoskeletal disorders is the most important cause of the loss of working timein work environments. Methods: For this cross sectional study samples were selected from workers employed in workshops of metallic products in Isfahan city. Data were collected using TMW standard questionnaire. The obtained data were analyzed using SPSS software. Results: Relationships between physical work demands and disorders of the upper limbs such as shoulders, wrist, elbow, and hand, were examined using X2 statistical test and the results showed that there are significant relationships between these disorders and the physical work demands. Conclusion: If exceed the work ability of a person work demands, as important factors in job doing, have a direct relationship with musculoskeletal disorders.