Fine needle aspiration cytology (FNAC) of the thyroid is a simple, accurate, fast, economical and safe method for the diagnosis of thyroid lesions on FNA. The objective of this study was application of pattern analysis in the interpretation of thyroid lesions. Two hundred and thirty three cases of thyroid lesion were reviewed, which had histopathological correlation. Smears were classified based on primary (predominant) and secondary (next dominant) pattern and categorized. The variation between combined and final cytological diagnosis was correlated with the histopathological diagnosis. The sensitivity, specificity and diagnostic accuracy for the diagnosis of malignancy were 90.47, 100 and 99.14 parts per thousand. Our study demonstrates the feasibility and applicability of pattern analysis in diagnosing thyroid lesions, which could be easily reproducible Diagn. Cytopathol. 2011. (C) 2010 Wiley Periodicals, Inc.