Their ubiquitous distribution and common occurrence in marine sediments make planktonic foraminiferal tests an ideal archive of past physical conditions of the upper oceans. However, their tests are prone to dissolution, especially in the deep sea. Their species-dependent removal from sediments is well-recorded, and is exhibited by the absence of some species after complete test disintegration, while others still remain. In order to further understand the dissolution process of planktonic foraminiferal calcite, we treated tests of Globorotalia cultrata, Globigerinoides ruber, and Neogloboquadrina dutertrei (315–355 μm intermediate diameter) with a weak buffered acetic acid. We recorded the number of intact tests and test weight during timed exposures to the acid. Effects ranged from excellent initial preservation to gentle, moderate, and severe dissolution and complete disintegration. Progressive dissolution is indicated by a linear decrease in the number of complete tests. While all three species show continuously decreasing test weight (when subjected to treatment with acid), discus-shaped tests of G. cultrata were more prone to dissolution, losing twice as much calcite as the globular tests of G. ruber and N. dutertrei.