Primary hyperparathyroidism is the most common cause of hypercalcemia in outpatients and it is usually attributed to parathyroid adenoma, which is managed by surgical resection of the adenoma. Successful management requires accurate localization of the adenoma prior to surgery. Objective: To describe our institution's experience in assessing the diagnostic value of parathyroid Fine Needle Aspirate (FNA) and PTH washout in localizing and confirming parathyroid adenoma. Methods: Twenty three patients (91.3% females) diagnosed to have primary hyperparathyroidism(PHPT) were enrolled in our study: parathyroid scanning (sestamibi), Ultrasound (US)and USguided FNA of the suspected parathyroid adenoma done to all patients by the same radiologist. The aspirate form FNA was washed out with one centimeter cubic normal saline and PTH was measured in the washout. Results: Mean(±SD) age was 51.3±13.5 year. Mean serum PTH (289.3±384.7) pg/ml and mean serum Calcium was (10.9±1.2) mg/ dl. Mean (±SD) PTH values in the washout is1172.3 ± 1877.6 pg/ml. Three patients had negative sestamibi scan but had positive results in PTH washout. The sensitivity and specificity of PTH washout are 82% and 100% respectively, with 100% positive predictive value and 67 % negative predictive value. For Sestamibi scan are 76.5% and 83.3% respectively with 92.9 % positive predictive value and 55.6 % negative predictive value and for ultrasound are 76 % and 67 % respectively with 87% positive predictive value and 50% negative predictive value. Conclusion: This study highlights the superiority of Parathyroid FNA with PTH washout over US or sestamibi scanning in confirming a parathyroid adenoma.