a cross-sectional study among 1,026 oil drilling workers in northeast brazil found a prevalence rate of 5% for intervertebral disk disease, varying from 1.8% (activities without heavy lifting) and 4.5% (occasional lifting) to 7.2% (routine lifting). disease prevalence was 10.5% among drilling workers with more than 15 years in the industry and 11.3% among those over 40 years of age. prevalence ratio (pr) for the association between working in oil drilling operations and intervertebral disk disease was 2.3 (95% ci: 1.3-4.0). retrospective information about exposure was collected to minimize the healthy worker survival effect. using information on current occupation instead of occupational life history would cause an underestimated pr of 1.1 (95% ci: 0.6-1.9). logistic regression showed results similar to the tabular analysis. neither confounding nor interaction was evident. growth of the brazilian oil industry and recent changes in the work force contract and management, involving changes in risk management and health control, indicate a need for prompt ergonomic intervention in order to control intervertebral disk disease among oil drilling workers.