Background: Vascular remodeling in idiopathic pulmonary fibrosis (IFF) is regulated by an imbalance between angiogenic and angiostatic factors. The identification of biomarkers for IFF could aid in the classification of disease subtypes, and provide a means to define therapeutic re­sponse. Endostatin is an anti-angiogenic peptide with known ef­fects on endothelial cells. VEGF xxxb is a new family of VEGF isoform stim­ulates a unique pattern of VEGF-R2 receptor with anti-angiogenic activity and play important role in lung injury and repair. The present study exam­ined weather the expression of endo-statin and VEGF xxxb differed among the histologic subgroups of IFF, usual interstitial pneumonia (UIP) which is steroid unresponsive type and non­specific interstitial pneumonia (NSIP) which is steroid responsive type. Methods : The present study was conducted retrospectively using lung biopsies collected via vidoscopic tho-racscopy from 10 patients diagnosed as UIP and 10 patients diagnosed as NSIP pathologically. The control lung tissues from 6 patients were ob­tained from histologically normal are­as of lung lobe removed for isolated benign tumors. The expression of en-dostatin and VEGF xxxb in lung tis­sues was assessed using immunohis-tochemistry studies.