The objective of this study was to examine the relationship between physical and psychological risk factors on the one hand, and the occurrence of new episodes of back pain on the other hand. A prospective study was conducted with 12 months follow-up by means of self-administered questionnaires. The study took place in the Cargo Department of a major Dutch airline company. The subjects for this study were 270 workers involved in heavy physical work. Only workers without back pain at baseline were included. Self-reported back pain and sick leave due to back pain during the follow-up period were measured. Of the 238 workers included in the analysis, 73 (31%) developed a new episode of back pain during the follow-up period, and 27 (11%) subjects reported sick leave due to back pain. Multiple logistic regression analysis showed that the history of back pain was the best predictor for the occurrence of a new episode of back pain during follow-up (OR 9.8; 95% CI 2.8-34.4 for subjects who had back pain more than twice in the past year). Low job satisfaction was also associated with an increased risk for the occurrence of back pain during follow-up (OR 1.2; 95% CI 1.01-1.4). Riding a forklift truck appeared to be a protective factor for the occurrence of back pain (OR 0.7; 95% CI 0.5-0.99). In this study the best predictors for the occurrence of back pain were the history of back complaints and low job satisfaction. Although it needs to be confirmed by future intervention studies, the results indicate that increasing job satisfaction may be a successful (co-)intervention for the prevention of back pain at the workplace. Copyright (C) 1998 International Association for the Study of Pain. Published by Elsevier Science B.V.