Hyalinizing trabecular adenoma is an uncommon benign thyroid tumor that is recently described in the literature. This tumor is easily confused with medullary carcinoma on surgical specimens and with papillay carcinoma on cytologic specimens. Herein we report the cytologic characteristics of a case of histologically proven hyalinizing trabecular adenoma of the thyroid gland. Cytologically, the aspirate showed trabecular or individually dispersed polygonal cells with finely stippled chromatin pattern, nuclear grooves, and eosinophilic nuclear pseudoinclusions. No colloid materials were noted in the background.