An investigation is in progress to determine risk factors for the development of noise-induced hearing loss in Canadian Forces personnel. A total of 1057 individuals representing a wide range of military trades have contributed their current audiogram, first audiogram on record, and responses to a 56-item questionnaire. The protocol for the hearing test was standardized and conformed to current audiological practice. The items included in the questionnaire related to demographics, occupational and nonoccupational noise exposure history, training in and utilization of personal hearing protectors, and factors other than noise which might affect hearing (e.g., head injury, ear disease, exposure to solvents, and the use of medications). Analyses are underway to determine the average current hearing thresholds as a function of frequency and change relative to baseline values at recruitment for groups defined by trade, rated noise hazard, and years of service. Preliminary results suggest ways to improve the training of personnel with respect to the effects of both occupational and nonoccupational noise exposure and methods of implementing hearing conservation strategies. The role of head injury, history of ear disease, and the use of medications appear to be small. [Work supported by Veterans Affairs Canada.]