In this retrospective histologic study, galectin-3 had a sensitivity of 92% (22/24) for papillary thyroid carcinoma and 44% (4/9) for follicular thyroid carcinoma. Thyroid peroxidase (TPO) had a sensitivity of 50% (12/24) for papillary and 11% (1/11) for follicular carcinoma. The combination of galectin-3 and TPO had a sensitivity of 96% (23/24) for papillary and 44% (4/9) for follicular carcinoma. From a prognostic standpoint, of patients whose papillary carcinomas expressed both markers, all became free of disease. Of those whose papillary carcinomas expressed galectin-3 but not TPO, 57% (4/7) became free of disease, 29% (2/7) had persistent disease, and 14% (1/7) had progressive disease. This study confirms previous observations that galectin-3 alone is highly sensitive for papillary carcinoma but not adequately sensitive for follicular carcinoma. TPO alone is not adequately sensitive for the evaluation of any thyroid lesion. The combination of galectin-3 and TPO is complementary as a diagnostic and prognostic tool for patients with papillary carcinoma.