Workers' compensation claims for hearing loss increased two-fold during 1984-1991 in Washington State. This population-based descriptive study examined 27,019 claims filed during 1984-1998 and accepted for hearing loss, in the workers' compensation jurisdiction that covers nearly all non-federal workers in Washington State. The number of claims increased 12-fold during 1984-1998. The annual incidence reached 2.6/1,000 workers statewide, and 70/1,000 in the most impacted industry. The increase involved all ages over 35 years, especially claimants over 65 years. Only 4% of providers accounted for 66% of claims. Most claimants (90%) received permanent partial disability compensation. In 1998, identifiable costs exceeded $57 million dollars. The striking increase in claims is probably largely due to reporting phenomena unrelated to current work circumstances. However, occupational hearing loss is probably much more common than usually recognized, and contemporary workers may still face substantial risk for hearing loss.