Social factors of 179 operated and 97 non-operated patients one year after hospitalization due to low back pain and sciatica were tested by multi-variate regression analysis in relation to the five-year outcome evaluated according to the WHO Handicap Classification. For operated men a subjective working incapacity (relative risk RR = 4.6) and co-morbidity (RR = 2.7) predicted a poor outcome. For operated women the predictive factors were subjective working incapacity (RR = 3.2) and older age (RR = 1.9). For non-operated men an increased occurrence of occupational hazards (RR = 3.6) and for non-operated women co-morbidity (RR = 7.1) indicated a poor outcome.