Microfossil analysis of human dental calculus provides consumption-specific and archaeologically relevant data for evaluating diet and subsistence in past populations. Calculus was extracted from 114 teeth representing 104 unique individuals from a late 16th to early 18th century skeletal series on Rapa Nui (Easter Island) to address questions of human–environment interactions and possible dietary preference. Scanning electron microscopy was used in lieu of optical microscopy for its superior depth of field and resolution of surface detail. The calculus microfossil recovery produced 16,377 total biogenic silica microfossils: 4733 phytoliths and 11,644 diatoms. The majority of phytoliths correspond with the Arecaceae or palm family (n = 4,456) and the minority corresponds to the Poaceae or grass family (n = 277). Because of the relatively large sample size, we were able to test hypotheses related to age cohort, sex, dental element and geographic region. Results indicate no significant difference in phytolith or diatom recovery based on age cohort or sex. The high frequency and proportion of Arecaceae phytoliths found in calculus extracted from the anterior dentition suggests consumption of soft or cooked foods containing palm phytoliths and the high frequency of diatoms recovered from the southern part of the island argue for different sources of drinking water. Copyright © 2012 John Wiley & Sons, Ltd.