The effects of exposures to noise and solvents on hearing loss among petroleum refinery workers were examined. A total of 438 workers from various departments of a South American oil refinery were interviewed and tested for hearing loss via otoscopy, pure tone audiometry, and immittance measurements. The subjects consisted of 89 workers from the aromatic and paraffin facilities, 40 workers from the shipping department, 180 maintenance crew workers from the aromatics and alkylation facility, 19 former aromatics workers, 69 workers from the quality control laboratory, and 41 warehouse and health clinic workers who served as the comparison group. Noise levels averaged 87 to 88 decibels (dBA) in the aromatic and paraffin facilities and 89dBA in the aromatics and alkylation facility. In other departments, noise exposures were not significant. Solvent exposure levels were determined by NIOSH during a workplace survey. High frequency hearing loss was significantly more prevalent among workers exposed to solvents and/or noise than among warehouse and health clinic workers or laboratory workers. According to multiple logistic regression analysis, age and work in the maintenance or shipping departments were significant predictors of hearing loss. Based on acoustic reflex measurements, there were significant differences among the groups in reflex decay, but not in the absence or elevation of the reflex. At frequencies of 500 and 1,000 hertz, acoustic reflex decay was significantly more prevalent among aromatics workers and pipe fitters than among the other workers. The authors conclude that combined exposure to noise and solvents influences audiometric thresholds and induces hearing loss in refinery workers.