Matching the worker and the job has been associated with reductions in work-related injuries and illnesses, and improvements in job performance and job satisfaction. There are two approaches: (a) selecting and training the worker to fit the job, and (b) designing the job to fit the worker (i.e., ergonomics). Most authorities prefer (b). Although job design may be applicable to many manufacturing operations, there are other jobs that are difficult to design and control and require greater dependence upon preplacement testing and selection of workers. The challenges in developing preplacement testing are (a) finding effective selection criteria, and (b) using these criteria without discriminating against handicapped, older, and female workers. In the developed countries, the most common and costly musculoskeletal disorder in industry is low back pain. Selection techniques for identifying those susceptible to low back pain can be grouped into medical examinations, strength and fitness testing, and job rating programmes. Medical examinations comprise the medical history, physical examination and, occasionally, low back X-rays. The history is important, since those who have had one episode of low back pain are more likely to have another. A careful history and thorough examination will detect about 7 or 8% of younger workers prone to back problems. The estimate is higher for older workers. The addition of low back X-rays may raise the effectiveness to 10% in younger workers. Routine X-rays are discouraged because the small yield does not justify the radiation exposure or cost Recent advances measuring the size of the spinal canal by ultrasound are promising. High isometric trunk strength and endurance appear to be related to lower levels of musculoskeletal injuries in industry. Dynamic strength testing is generally regarded as superior to isometric strength testing, but no objective evidence is available regarding its effectiveness as a selection criterion. A high level of fitness in fire-fighters has been related to a lower number of compensable cases of low back pain. Job rating programmes have not been objectively evaluated for their effectiveness in reducing the incidence, severity, or cost of musculoskeletal injuries in the workplace. Preplacement testing and selection of workers can make a significant contribution toward reducing musculoskeletal injuries, but it must be supplemented by training, ergonomics, appropriate treatment, enlightened management, and cooperative unions.