In a population-based case-referent study, the occupational experience of 86 men with oral or oropharyngeal cancer and 373 referents was analyzed with respect to employment in 41 occupations and 40 industries, as well as to exposure to 16 chemicals, as estimated via a job-exposure matrix. Among the occupations and industries at higher risk were machinery operator (odds ratio [OR] 2.0; 95% confidence interval [95% CI] 1.0-4.0), plumber (OR 5.0, 95% CI 1.2-21.5), building industry (OR 2.5; 95% CI 1.3-4.5), textile industry (OR 2.5; 95% CI 0.6-4.6), and electricity production (OR 2.8; 95% CI 0.7-12.1). All the OR estimates were adjusted for age, education, area of birth, tobacco smoking, and alcohol consumption. An association between formaldehyde exposure and oral cancer was suggested (OR for any exposure 1.6, 95% CI 0.9-2.8; OR for probable or definite exposure 1.8, 95% CI 0.6-5.5). No other chemical included in the matrix showed any risk pattern. The evidence of an association between formaldehyde exposure and oral or oropharyngeal cancer is strengthened by the results of this study.