Abstract: Introduction: Oral submucous fibrosis (OSMF) is considered to be hot topic among medical & dental fraternity throughout the world, particularly in India, because around 0.5% population got affected yearly that posing a major health problem. Besides OSMF, oral squamous cell carcinoma (OSCC) apprehends majority oral malignancies, studies have proved OSMF has got 7 to 13% malignant potential. Therefore,the study was carried out to learn the collagen fiber histopathologically for the orientation and thickness of collagen fibers in OSMF, OSCCand OSCCwith OSMF with picrosirius red staining and was examined with polarizing microscope.Material & method: Each fifteen cases of histologically diagnosed, OSMF, OSCC and OSCC with OSMF were taken for the study and fivespecimen of normal buccal mucosa were also incorporated as a control group. All were stained with haematoxylin, eosin and picrosirius red staining for evaluation under polarised microscope. Result:The result of the study showed, there is a gradual change in birefringence of collagen fibers from red to orange red to yellowish green as from OSMF to OSMF with OSCC and to OSCC. Conclusion: The conducted study indicated that the change in orientation and thickness of collagen fibers in OSMF could acts as a prognostic marker indicative of malignant transformation.