ObjectiveTo assess fine needle aspiration (FNAC) in the early diagnosis for auto immune thyroid disease (AITD) in adolescent.Methods Seventy-one patients, age ranging from 9 to 23 years with thyroid enlargement underwent FNAC. Their smears were classified into 4 types according to the degree of degeneration of adenoidal cell and lymphocyte invasion by HE combining with rapid staining.The results were compared with B ultrasound and serum thyroid auto antibody measurement.ResultsB ultrasound showed hyperthyroidism in 12 cases, inflammation in 53, nodule change in 5, normal in 5. Thyroid function examination demonstrated hyperthyroidism in 22 cases, hypothyroidism in 9 cases, and euthyroidism in 40 cases. Auto thyroid antibody (TGAb,TMAb) were all beyond normal range except in 1 case, and TPOAb elevated in 37 cases. FNAC identified Grave′s disease in 14, Hashimoto′s diseases typeⅠ( HT-Ⅰ) in 35 cases,HT(Ⅱ) in 13,HT(Ⅲ) in 3, and HT(Ⅳ) in 6 cases. ConclusionsFNAC contributes to early diagnosis of AITD in adolescent for its safety, simplicity, rapidity and accuracy.