We describe unusual manifestations of congenital cystic adenomatoid malformation ( C.C.A.M.) of the lung, such as movable fungal ball-like intracystic blood clots and hemoptysis, which were detected in previously healthy 23 years-old woman. We identified blood clots only after left upper lobectomy and could not distinguish from fungal ball with radiographic methods. CCAM of the lung, rare and lethal form of congenital pulmonary cystic disease, was initially introduced by Ch'in and Tang in 1949. The histogenesis of this lesion is characterized by polypoid glandular tissue proliferation and overgrowth of mesenchymal elements due to cessation of bronchiolar maturation which occured in after 16weeks intrauterine period. In 80-95% of reported cases, the lesion was confined to a single lobe and there was no lobe and right and left lung predilection. The clinical presentation may be widely variable, ranging from intrauterine fetal death to late discovery in childhood with recurrent pulmonary infection. But there's no reports which were misdiagnosed with intracystic fungal ball. The treatment choice is lobectomy of affected lobe. There's a few case reports with rhabdomyosarcoma, bronchiolar cell carcinoma and myxosarcoma arising in CCAM patients. Therefore, early resection is recommended even if asymtomatic cases. We experienced a rare case of CCAM of the lung in 23 years old female, and there were intracystic fungal ball-like movable blood clots in lower portion of left lung. After left upper lobectomy was performed, now she is discharged and followed up without any complications.