Back pain is a major source of lost work time. Occupational physical activity only accounts for a fraction of low back pain; therefore, there is growing interest in investigating other possible causes of back pain including the psychosocial work environment. Material handlers (N = 6,311) in 160 newly opened stores were interviewed at study entry and approximately 6 months later. Factor analysis was used to reduce the 37 psychosocial questionnaire items to seven distinct factors. After adjusting for history of back problems and work-related lifting, risk of back pain was moderately increased among employees who reported high job intensity demands (odds ratio (OR) = 1.8), job dissatisfaction (OR = 1.7), and high job scheduling demands (OR = 1.6). Modification of the psychosocial work environment for material handlers in large retail stores may help reduce back pain among employees.