This is a study of the effectiveness of interventions to reduce the physical work demands associated with manual (materials) handling in the work situation and musculoskeletal symptoms in the longer term. A systematic electronic literature search between 1990 and February 2003 was performed in 5 databases: Embase, Medline, HSE-line, Nioshtic, and Nioshtic-2. 44 studies were reviewed. The interventions were divided into two categories, (ergonomic) measures and implementation strategies. One randomized controlled field study was found that established a causal effect for a combination of implementation strategies in reducing the physical work demands associated with manual handling and reducing acute musculoskeletal symptoms. All four of the controlled field studies showed a significant reduction in the physical work demands when lifting devices were part of the intervention. Two of these studies measured a significant reduction in low-back disorders in the longer term. Of the 26 implementation strategies, 21 that measured an improvement in the process variables (eg, aimed behavioral variables) used a participatory ergonomics approach, an education (or training) program or both with the direct involvement of workers. The review indicated that significant reductions in physical work demands and musculoskeletal symptoms were found when lifting devices were part of the intervention. In changing worker's behavior using facilitating and educational strategies is important.