It is well known that nuclear grooves play a major role in the diagnosis of papillary carcinoma thyroid. Also grooves are found in many non- neoplastic lesions of thyroid. To calculate the percentage of nuclear grooves in histopathologically proven cases of papillary carcinoma and non –neoplastic lesions (hashimoto’s thyroiditis and colloid goiter). This retrospective study was carried out by reviewing the data and cytology smears of 21 histopathologically confirmed cases of papillary carcinoma thyroid and 10 cases each of hashimoto’s thyoiditis and colloid goitre. The percentage of nuclear grooves was calculated in oil immersion by counting 100 to 500 cells depending on the cellularity. The percentage of nuclear grooving ranged from 15% to 85% in the papillary carcinoma cases. Greater than 20% nuclear grooves were observed in 19(90.4%) of the cases. Nuclear crowding and overlapping, pale chromatin, nuclear grooves, nuclear enlargement and prominent nucleoli were seen in all (100%) the cases. Intranuclear cytoplasmic pseudoinclusions were seen in only 5(23.8%) of the cases. Histiocytes, metaplastic cells and multinucleated giant cells were seen in 12(57.1%), 10(47.6%) and 6(28.5%) of the cases. The percentage of nuclear grooves in non neoplastic cases overall observed was <10%. The sensitivity and specificity of grooves for PCT at >=20% were 90.5% and 100% respectively. Whenever in doubt, a diagnosis of papillary carcinoma can be offered confidently by this semiquantitative approach for grooves in combination with other features.