Preplacement screening is put forth by some as an effective method for preventing low back disability at the workplace. Although there are still large gaps in knowledge regarding the natural history of and risk factors for back disability, it is clear that the majority of costs are derived from the small proportion of those that will suffer with back symptoms for 6 months or more. Thus, if preplacement screening is to have an impact on health care spending and compensation costs, the screening test will have to be predictive not so much of all back injuries, but rather of work absenteeism and especially chronic disability. This paper presents some criteria for evaluating a screening program and explores the effect of choosing different outcomes for evaluation. The literature on the effectiveness of a number of preplacement screening techniques is examined. Current legislation related to preplacement screening is also described. The natural history, etiologic factors, and prognostic markers for back injuries need to be elucidated further before effective screening strategies can be developed to reduce the incidence of back injuries and back disability in the population.