Introduction: Musculoskeletal disorders (MSDs) are one of the main problems in workplaces, which cause loss of working time, absenteeism, reduced workers’ efficiency and increased service and production costs. The present study was carried out to investigate the prevalence of musculoskeletal disorders and their associated risk among office workers.

Methods: In this descriptive cross-sectional study one hundred and thirty three office workers of a huge construction company were involved. For collecting data related to musculoskeletal symptoms and to investigate the associated risk of these disorders the Nordic standard questionnaire and RULA method were used, respectively. Data were analyzed with chi-square test and multiple regressions by using SPSS software version 16.

Results: About 50% of the workers reported MSDs’ symptoms, during the past 12 months, at least in one region of musculoskeletal system. The highest prevalence belonged to lower back (42.1%), neck (33.1%), wrist (18%), and shoulders (11.3%), respectively. The prevalence of symptoms in the neck and lower back of workers, with more than 10 working hours per day, was statistically significant (P>0.001). Additionally, a statistically higher prevalence of symptoms in the neck, wrist, and lower back of workers with job tenure higher than 5 years was noted (P>0.05). The risk assessment revealed that all workers’ postures were fall into action levels of 2 and 3.

Conclusions: The findings revealed that MSDs symptoms have a high prevalence in office workers and the risk of these disorders is intermediate to high. Moreover, the main effective factors in the prevalence of MSDs symptoms were job tenure higher than 5 years and working hours more than 10 per day.