A systematic review of more than 800 investigations of serious and fatal occupational accidents with the purpose of identifying psychosocial risk factors involved as a basic cause of these events. Which are the most frequently identified? Which are associated with serious occupational accidents and which with fatal accidents? What are the impediments to identifying these factors in an investigation? Are there accident investigation methodologies more likely to identify these factors? Are the investigators trained to identify the existence of psychosocial factors in the accident? These are some of the questions contained in this document.