PURPOSE: This study aimed to evaluate the expression pattern of Galectin-3 and β-catenin and to assess the nuclear morphometric features of different thyroid lesions to investigate their diagnostic significance. METHODS: Sixty specimens of benign and malignant thyroid lesions, in addition to 10 cases of normal thyroid tissue used as control, were immunohistochemically stained with antibodies against galectin-3 and β-catenin. Hematoxylin and Eosin stained slides were examined using image analyzer Proplus V software. Morphological parameters measured included mean nuclear diameter, mean nuclear perimeter and mean nuclear area. RESULTS: Cytoplasmic immunoreactivity for galectin-3 was strongest in papillary thyroid carcinomas (88.9%), whereas staining was less intense in follicular variant of papillary thyroid carcinoma and in follicular (60% and 75% respectively) and poorly differentiated carcinomas (28.6%), and expressed focally and weakly in follicular adenoma cases and even weaker in the reactive follicular epithelium of nodular goiter (P < 0.5). Membrane β-catenin expression was decreased in only two out of 13 (15.4%) adenomas and in 21 out of 38 (55.3%) of carcinomas (P < 0.5). Among carcinomas, reduced membrane β-catenin was associated with progressive loss of tumor differentiation and increased invasiveness (P < 0.5). Mean nuclear diameter and the mean nuclear perimeter were higher in undifferentiated carcinomas when compared to other subtypes and were the least for follicular neoplasms. CONCLUSIONS: Galectin-3 immunostaining and analysis of β-catenin dysregulation may be useful as an adjunct to distinguish benign from malignant thyroid lesions. Quantitative estimation of nuclear features can play a role in assessment of the morphological features and so helping in diagnosis of thyroid lesions.