The present study was carried out to investigate the possible etiology and pathology of cystic ovarian follicles by determining the expression levels of mRNA for LH-r gene in follicular cells of dominant follicles in comparison with cystic ovarian follicles in Iraqi cows. This study were performed in two steps, firstly aspiration of follicular fluids from dominant follicles and cystic follicles and stored in (-20 ℃) until estradiol and progesterone assay, secondary section of the follicular wall in to two hemispheres, and stored at -70 ℃ to -80 ℃ to molecular study. The macroscopic examination of the ovaries revealed that the numbers of dominant follicles are [1] samples while cystic follicles were in [2] samples. There was a significant difference (P<0.05) in the diameter of cystic ovarian follicles (37.56 ± 0.64 mm) compared with dominant follicles (19.93 ± 0.32 mm). Results of hormonal assay showed higher estradiol-17β (865.96±10.64 ng/ml) and progesterone (84.8±1.35 ng/ml) concentrations in follicular fluids of cystic ovarian follicles, which were significantly higher (P<0.05) in comparison with those of dominant follicles which were (314.39±2.55 ng/ml) and (50.25±1.57 ng/ml) respectively. Molecular study, to evaluate the relative quantification of LH-r gene in dominant and cystic follicular cells, has been done by extraction of the total RNA and assay its concentration from these cells, synthesis data of the complementary DNA (cDNA), that done by reverse transcription PCR (q-RT-PCR) technique, of target gene and compared of the gene expression in dominant and cystic follicular cells, the our results referred to down regulation of LH-r gene expression in follicular cells of the cystic ovarian follicles, that may be assistance to understand the etiology and pathology of this case (disease), thus the up-regulation of the this gene in cells of dominant follicles may explain the important role of the LH in ovulation mechanism and increasing follicular ovulation chance.