PURPOSE: This paper is to evaluate radiological features of hypersensitivity pneumonitis, correlated with clinical and pathologic findings. MATERIALS AND METHODS: Patients consisted of 2 men and 3 women, aged 23-51 years old (average 41). Diagnosis was based on the presence of suggestive clinical and radiological findings (chest radiography, high resolutional CT, gallium scintigraphy), and lung biopsy showing characteristic histological features. RESULTS: All patients complained of exertional dyspnea and three patients experienced coughing. On the pulmonary function test, four patients revealed restrictive pattern and one patient was normal. Results of bronchoalveolar lavage, available in four patients, revealed lymphocytosis in three patients and normal finding in one patient. Chest radiographs showed ground glass opacity or diffuse nodular densities. On the HRCT, diffuse nodular opacity and ground glass opacity were seen in variable features. All 4 patients had diffuse increased uptake on the gallium scan. On lung biopsy, a combination of histologic findings showed cellular bronchiolitis, diffuse interstitial infiltrates and non-necrotizing granulomas, consistent with diagnosis of hypersensitivity pneumonitis. CONCLUSION: Hypersensitivity pneumonitis could be diagnosed with these radiological, clinical and pathological findings.