Pulmonary blastoma is a rare lung tumor resembling fetal lung tissue. Pathologically the tumor can be classified to 2 groups, well-differentiated fetal adenocarcinoma(WDFA) and biphasic blastoma. WDFA has more favorable prognosis with fewer metastasis at initial presentation and fewer recurrence after treatment. We experienced a case of pulmonary blastoma in 32-year-old female patient. The patient was referred to our hospital because of abnormal mass shadow in right middle lobe. The diagnosis of pulmonary blastoma(WDFA type, Stage I T2NOMO) was confirmed after right middle lobectomy. We followed up 22 months without an evidence of recurrence.