Retrospective studies, providing direct evidence of temporal changes in forest soil chemistry, are relatively rare due to a lack of appropriate sampling, documentation, and archiving of samples from forest soils prior to the last few decades. We were provided an unusual opportunity to conduct such a retrospective study with relocation of four sites on the Allegheny Plateau in Pennsylvania that had been sampled and archived in 1967 as part of a county soil survey. Additionally, an original investigator came out of retirement to insure field sampling protocol consistency with resampling in 1997. Reanalysis of archived samples yielded similar results to those published in 1970, despite some method differences. At all four sites, comparison of 1967 and 1997 samples showed significant decreases in exchangeable calcium (Ca) and magnesium (Mg) concentrations and pH at all depths. Exchangeable aluminum (Al) concentrations increased at all depths at all sites, however increases were only significant in upper soil horizons. Shorter-term temporal changes estimated by sampling the A horizon annually for 3 years were insignificant, suggesting that the differences between 1967 and 1997 sampling are part of a longer-term trend. Comparison of changes in soil nutrient capital with estimates of net storage in forest biomass was less clear, pointing out difficulties in addressing such dynamics from a budgetary point of view. Although few retrospective studies of this type have been reported, we suspect that of the many county soil surveys conducted, stored samples and intact sampling sites may provide other opportunities for retrospective studies.