Objectives: Inthisstudy,weaimedtodeterminethemorphological changes in the organ of Corti in the basal, medial, and apical regions of the cochlear canal, which exhibit a complex structure.Materials and Methods: A total of eight male Wistar albino rats (35 days, 200 to 250 g) were decapitated under anesthesia. The organ of Corti was quickly removed and fixed in 10% formaldehydesolutionforhistologicalexamination.Thetissues were, then, taken to decalcification solution. Following dehydration and clearing, they were embedded in paraffin. Sections were stained with hematoxylin & eosin and Masson's trichrome,andphotographswerecapturedusingalightmicroscope. To determine the structural changes in the organ of Corti, basilar, tectorial, and Reissner membrane lengths, and heights of inner and outer hair cells were measured from 50 different areas using the Image J software and the data obtained were statistically evaluated.Results: It was determined that from the basal to the apex of the cochlea; the thickness of the basement membrane and the length of the Reissner's membrane decreased, while the length of the inner and outer hair cells and the length of the basement membraneincreased.Theseincreasesanddecreaseswerestatistically significant (p<0.05).Conclusion: Our study results suggest that the lengths of inner and outer hair cells, basilar, and Reissner membrane can vary from basal to apical region of the cochlea.