Analysis of scales taken at the times of tagging and recapture from 74 Dover solesMicrostomus pacificuscollected off Oregon demonstrated that scales were inadequate aging structures for this species. This contradicted earlier work that used marginal growth of scales and age–length observations as indirect validation methods. Errors in scale-age determinations were found for fish assigned scale ages of 5 years and greater. For female Dover soles, the probability of increment (“annulus”) formation was greater for younger than for older fish. Relationships between expected scale age and actual age indicated that maximum longevity of this species off Oregon may be in the range of 48–52 years, in contrast to the maximum scale age of 28 observed for this species.