Several histological and immunohistochemical techniques are used in the diagnosis of fibrosis. To better visualization of collagen fibers in both normal and pathological tissues, new optical approaches are required.The present study aimed toinvestigate/compare the efficiency of various histological stains, using the traditional light microscope and the light polarizing microscope, to quantify/evaluate the ovarian and oviduct fibrosis induced by high-fat diet (HFD) consumption. Twenty-Four female albino rats (Rattus norvegicus albinus) were randomly allotted into 4 groups (n=6): control groups (fed on standard diet for 6 and 12 weeks), HFD1 group (fed on HFD for 6 weeks), and HFD2 group (fed on HFD for 12 weeks). The ovarian and oviduct fibrosis were investigated via histological stains including hematoxylin and eosin, Picrosirius Red, van Gieson, and Masson's trichrome stains using traditional light and polarizing light microscopes, in addition to immunohistochemical demonstrations of α-smooth muscle actin (α-SMA) and vimentin. Hydroxyproline and tumor necrosis factor-α (TNF-α) were also investigated biochemically in the ovarian and oviduct tissues. The results showed that the HFD induced ovarian and oviducts fibrosis in time-dependent manner with significant increases in hydroxyproline and TNF-α values, as well as immunoexpression of α-SMA and vimentin. Picrosirius red stain achieved ideal results in collagen demonstration when compared with van Gieson and Masson's trichrome stains. Picrosirius red stain in combination with the polarization microscope represented high sensitivity in collagen estimation in comparison with light microscopy. This work recommended using polarizing microscope as a tool to evaluate fibrosis of both the ovaries and the oviducts.