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Eosinophilic Granulomatosis Polyangiitis a systemic autoimmune disease characterized by granulomatous inflammation of small and medium arteries and veins, which may be presented with pulmonary infiltrations, peripheral blood eosinophilia, nasal polyps, mononeuritis multiplexes, cardiomyopathy, purpura and/or cutaneous nodules. The incidence of the disease is similar in males and females, and is usually diagnosed in the 3rd-4th decades. Sometimes pulmonary involvement of vasculitis can mimic lung cancers. A 51-year-old male patient with cough, dyspnea and weight loss was referred to our clinic with a suspicion of lung malignancy because of the presence of nodules and lymphadenopathies on thorax computed tomography (CT). Thorax CT revealed mediastinal and hilar enlarged lymph nodes, a ground-glass nodule in the right lower lobe, nodular lesions in the right upper and middle lobe and both lower lobes. The patient’s history revealed that he had been suffering from asthma for 20 years, receiving salmeterol-fluticasone and montelukast treatment, and a history of chronic sinusitis and nasal polypectomy. Patients also noted periodic skin rash occur. Physical examination was unremarkable. The montelukast therapy was discontinued due to elevated peripheral blood eosinophil count (1400/mL). Other hemogram and biochemistry values, sedimentation rate, C-reactive protein level were normal. Anti-neutrophil antibody, anti-neutrophil cytoplasmic antibody (ANCA), serum autoantibodies as biomarkers for connective tissue diseases were also negative. Total IgE level was 328 IU/mL (0-114 IU/mL). Skin prick tests were negative. Pulmonary function test (PFT) revealed mild obstructive ventilatory defect. Paranasal CT showed chronic sinusitis bilaterally. The patient uderwent fiberoptic bronchoscopy (FOB) and endobronchal lesion was not detected. Bronchoalveolar lavage (BAL) fluid were sampled from middle lobe. BAL fluid showed no malignancy, besides the cell count revealed an eosinophil rate of 88%. According to clinical, laboratory and radiological findings, the patient was diagnosed as ANCA negative eosinophilic granulomatosis polyangiitis and 0.5 mg/kg/day methylprednisolone treatment was initiated. Significant clinical and radiological improvement were obtained in the third month of treatment with an increase of 700 mL in forced expiratory volume-one second (FEV1) was detected in the control PFT. The case was presented to emphasize the necessity of considering pulmonary involvement of vasculitic diseases in the presence of nodules and mediastinal lymph node enlargement radiologically with accompanying systemic findings.