Recent increases in the number of thyroid fine-needle aspiration (FNAs) biopsies and the popularity of on-site evaluation for adequacy (OSEA) have led many practices, including ours, to rely on cytotechnologists for performing OSEA. We retrospectively analyzed the accuracy of a cytotechnologist against that of a cytopathologist in performing OSEA and making the final diagnosis. Of 2,261 thyroid FNA specimens evaluated over a 33-month period under ultrasound guidance with OSEA, the cytotechnologist attended 64.7% (1,462/2,261) of the procedures whereas the cytopathologist attended 35.3% (799/2,261). There was no difference in the adequacy downgrade rate for cytotechnologists compared with that for cytopathologists during this study period (4.1% vs 5.0% downgrade rate, P = .33). Regardless of who rendered the OSEA, subadequate specimens had a higher rate of indeterminate diagnosis (25.2%) than those specimens deemed adequate at the time of OSEA (11.9%, P = .00001). These results indicate that the accuracy of cytotechnologists is comparable with that of cytopathologists in conducting OSEA of the thyroid.