en Prediction of Malignancy in Thyroid Nodules; A Retrospective Comparative Study Aim: This study assessed the potential of malignancy in patients presenting with clinically solitary thyroid nodules and compared the histopathology of excised samples and sonographic characteristics and fine-needle aspiration cytology results. Participants & Methods: This retrospective study was conducted over three years on data from 140 patients attended general surgery outpatient departments at Al-Sader Teaching Hospital and a private clinic with different complaints of solitary thyroid nodules. The collected data included initial diagnoses according to the results of clinical assessment, ultrasound evaluation, fine-needle aspiration cytology, and histopathological examination. Findings: As confirmed by histopathological examination, the prevalence of malignancy in clinical solitary thyroid nodules was 9.29% with male patients affected more than females (15% vs. 8.33%). Clinical assessment was a poor predictor for malignancy, as it was associated with a low sensitivity rate (69.23%), which means high false negative results, despite its high specificity rate (92.91%). According to the ultrasound examination, most malignancies were found in solid and mixed nodules (85% and 15%, respectively) with a significant association between the nature of nodules and malignancy potential. Fine-needle aspiration cytology was the most sensitive and specific investigation of thyroid nodules, it combined both high sensitivity and specificity for diagnosing malignant thyroid nodules (90.91% and 97.65%) respectively. Positive and negative predictive values were 79.83% and 99.06% respectively with an overall agreement of 97.02%. Conclusion: Fine-needle aspiration cytology is a minimally invasive diagnostic tool for the early detection of malignancy among patients with solitary thyroid nodules, which combines high degrees of both specificity and sensitivity with a high accuracy rate of 97.02% comparable to histological examination. Ultrasonography,Thyroid Nodule,Cytology,Thyroid Gland, 99 104 http://ijwph.ir/browse.php?a_code=A-10-2162-1&slc_lang=en&sid=3 Q.K. Baqir 1003194753284600379347 1003194753284600379347 No Department of Surgery, College of Medicine, University of Basrah, Basrah, Iraq S.F. Abbas 1003194753284600379208 1003194753284600379208 Yes Department of Pharmacology, College of Medicine, University of Basrah, Basrah, Iraq F.K. Baqer 1003194753284600379047 1003194753284600379047 No Department of Surgery, Al-Sader Teaching Hospital, Basrah, Iraq