Reproduction failure in Arabian mares is mainly attributed to endometritis. To achieve successful solutions to endometritis, several diagnostic methods must be combined. 36 mares were diagnosed with endometritis, and 69.4% of mares scanned showed abnormal echogenicity and echotexture of endometrium by ultrasonography. This was confirmed by endometrial cytology via low-volume uterine flush, whereas 63.9% of smears contained more than 2–3 PMNs per HPF X100. Additionally, 86.1% of mares were positive for microbial culture. Sequencing of different isolates revealed that Staphylococcus was 44.4% more prevalent than Brevundimonas 27.8%, and Alcaligenes 27.8%. The mares were allocated to four groups; G1 (n= 6) mares left without treatment as control. G2 (KAN, n= 10) mares received three IM doses of kanamycin 10%. G3 (DHS, n= 10) mares were given 3 intramuscular injections of dihydrostreptomycin. G4 (PRF, n= 10) 30 mL autologous platelets rich fibrin (PRF), freshly prepared 6 to 10 minutes at 20-25°C, which was infused intrauterine within 6 hours after natural mating via one-way catheter to obtain its optimum therapeutic benefits. Twice mating was performed within 24-48 hours after ovulation induction of 30 mm follicles using 2500 IU of HCG, IV. A single fertile stallion per group was used. A noteworthy decrease in the endometrial thickness (p<0.05) between groups with an average of 8.35±0.32 mm, besides subsiding of the retained black anechoic intrauterine discharges. Moreover, a significant (p<0.05) enhancement in pregnancy percentage was noticed between the treated groups comparison versus the control. It could be concluded that bacterial infection can be involved in endometritis in Arabian mares, and also autologous PRF can be applied as an inexpensive substitute treatment.