Introduction: Diseases of the thyroid gland include both benign and malignant conditions. Benign conditions include goiter, thyroiditis, and follicular adenoma. Malignant conditions include follicular, papillary, medullary, anaplastic carcinoma. Fine needle aspiration cytology (FNAC) of the thyroid gland is the first-line diagnostic test for the evaluation of diffuse thyroid lesions as well as thyroid nodules. The main purpose it serves is in confirming benign lesions and avoiding surgery in benign lesions. The most common investigations, a patient of thyroid lesion undergoes, include thyroid assay and FNAC. Materials and methods: This prospective hospital-based observational study includes all patients from January 2019 to June 2019, with thyroid lesions who will undergo FNAC, excisional biopsy of thyroid, and serum thyroid-stimulating hormone (TSH) level. In the department of pathology Mahatma Gandhi Medical College and Hospital, Sitapura, Jaipur (Rajasthan). Results: The study was undertaken on 60 patients with clinically thyroid lesions during a period of approximately January 2019 to June 2019. Most thyroid lesions in our study were benign (62%). Out of 39 cytological benign lesions, 2 on histopathological follow-up were found malignant, i.e., 5%, and the rest 37 cases were found benign, i.e., 95%. All of the 16 cytological malignant lesions on histopathological follow-up were found malignant, i.e., 100%. All of the five cytologically suspicious for malignancy were found malignant on histopathological follow-up, i.e., 100%. In the present study, maximum number of benign cases, i.e., 14 cases (38%), were found to have serum TSH levels in the range of 0.40–1.39 μIU/mL, and the maximum number of malignant, i.e., 13 cases (53%), were found TSH in the range of 5 μIU/mL or more on the basis histopathological diagnosis. In the present study, maximum number of benign, i.e., 15 cases (38.4%), were found to have TSH in the range of 0.40–1.39 μIU/mL, and a maximum number of malignant cases, i.e., 12 (57.14%), were found in the TSH range of 5 μIU/mL or more on the basis cytology diagnosis. Conclusion: There is a significant association between TSH and malignancy, TSH within high normal range and higher serum concentration TSH both are associated with a higher risk of thyroid malignancy.