Both idiopathic pulmonary fibrosis (IPF) and pulmonary involvement of collagen vascular disease (CVD) are well known cause of diffuse interstitial lung disease which lead to fibrosis and honeycombing. We analyzed HRCT findings of 33 patients with IPT and 14 patients with CVD in terms of predominant pattern, site of involvement, mediastinal lymph node enlargement, pleural change and pulmonary volume loss. Criteria of mediastinal lymph node enlargement and pleural thickening were 15mm in long diameter and 3mm, respectively. Volume loss of the lung was measured by using hilar height ratio (apex to hilum/hilum to diaphragmatic dome). Mean age was 61 years for IPE and 46 years for CVD and male : female ratio was 27: 6, 4:10, respectively. Predominant HRCT pattern was honeycombing for IPE (63%), and ground-glass opacity for CVD (66%) (p=0.001) Predominantly subpleural involvement was seen in 90% for IPE and 74% for CVD Mediastinal lymph node enlargement was seen in 47% of the patient with IPE and 14% with CVD (p=0.004). Pleural thickening was seen in 97% of the patients with IPE and 42% with CVD (p=0.002). Pleural effusion was seen in 10% of the patients with IPE and 36% with CVD (p=0.009). Hilar height ratio of more than 1.5 was seen in 84% of the patients with IPE and 29% with CVD. In conclusion, our study shows that patients with IPF are prone to have more progressed stage of pulmonary fibrosis than the patients with CVD on HRCT.