Background Thyroid nodules have become relatively common in clinical practice, and their prevalence increases with age. The majority of thyroid nodules are benign, with 5-15% being malignant. There are a number of well-established predictors of malignancy in thyroid nodules, but thyroid nodule size has been a cause for concern for many researchers and results of the studies are still controversial about their probability of malignancy. Up to the current knowledge, there is no published study that evaluates if thyroid nodule size is associated with the risk of malignancy in Saudi Arabia, so in this study, we aim to find that. Methods This is a retrospective study of 987 patients who underwent thyroid nodule fine-needle aspiration (FNA) and subsequent thyroidectomy for thyroid nodules measuring ≥ 1 cm. Results Thyroid cancer was more prevalent in males than females, and in patients who were older than or equal to 45 years. Nodular size of 1-1.9 cm was more prevalent among cancer patients than in benign cases (p<0.001). Conclusions The highest malignancy risk was observed in nodules <2 cm and no increase in malignancy risk for nodules >2 cm. Nevertheless, when examined by type of thyroid malignancy, the rate of follicular carcinoma and other rare malignancy increased with increasing nodule size.