This study was a 10-year follow-up of the associations between work content, work control, social relationships at work, mental overstrain, physical work load, and musculoskeletal morbidity in the neck, shoulder and upper limb region, the low back, and the lower limbs among workers in the metal industry.A sample of 902 blue- and white-collar employees were studied. Measurements were made twice at the a 10-year interval by questionnaire and clinical examination.At the beginning of the study, mental overstrain showed several associations with both the symptoms and the findings. The other psychosocial factors were the most consistently associated with the symptoms in the region of the neck, shoulder, and upper limbs and also in the lower-limb region among the middle-aged men. Prospectively, the social relations and the work content scores predicted the change in several morbidity scores. The associations were independent of physical work load.Work-related psychosocial factors were associated with, and predicted, the change in the occurrence of musculoskeletal disorders when age, gender, social class, and physical work load were controlled for.