The etiology of musculoskeletal disorders is complex, with physical and psychosocial working conditions playing an important role. This study aimed to determine the relationship between psychosocial work conditions, such as psychological job demands, decision latitude, social support and job insecurity and musculoskeletal complains (MSCs) and (repetitive strain injuries (RSIs) in a 1-year prospective study. The job content questionnaire, the Nordic musculoskeletal questionnaire and provocation tests were used to study 725 employees aged 20-70 years. Pain in the lower back (58 % of subjects), neck (57 %), wrists/hands (47 %) and upper back (44 %) was most frequent. The carpal tunnel syndrome (CTS) (33.6 %), rotator cuff tendinitis (15.4 %), Guyon's canal syndrome (13.4 %), lateral epicondylitis (7.6 %), medial epicondylitis (5.3 %), tendinitis of forearm-wrist extensors (7.8 %) and tendinitis of forearm-wrist flexors (7.3 %) were the most frequent RSIs. Logistic analysis showed that increased psychological job demands statistically significantly increased the probability of lateral and medial epicondylitis, and increased control (decision latitude) statistically significantly decreased the risk of CTS. There was no relationship between job insecurity, social support and the studied RSIs. Psychosocial factors at work predict prevalence of MSCs and RSIs, irrespectively of demographic factors, e.g., age or gender, and organizational and physical factors.