The diagnosis of malignancy in solitary thyroid nodules (STN) is difficult. This paper reviews 91 cases of STN that underwent surgery after fine-needle aspiration cytology (FNAC) at the Kuwait Cancer Control Centre. In discriminating between benign and malignant lesions, patient histories and clinical examinations were of some value and thyroid scans were of limited value, but FNAC was the most useful tool and correlated best with the histopathological assessment. Using FNAC alone, there were no false-positive diagnoses and only 1 false negative (1.9%). We suggest that FNAC is the most reliable of the various diagnostic tests and recommend its routine clinical use in solitary thyroid nodules.