A total numbers of 115 native breed mares were used in the present study. Uterine swabs were taken for bacteriological culture. The follicular growth and pregnancy were detected by rectal palpation and ultrasonography. There was a higher incidence of bacterial isolation from lactating mares (70.91%) than those in barren ones (43.33%). The mares were randomly divided into 9 groups which subjected to the following treatment regimers: 1) no drugs (control), 2) intrauterine infusion with 120 ml homologus plasma, 3) intrauterine infusion with 120 ml leukocyte enriched homologus plasma, 4) intrauterine infusion with antibiotics, 5) intravenous injection with 20 LU oxytocin giving 3 times post breeding and 6) intravenous injection with 20 1.U oxytocin giving once. The animalis groups from 1-4 were treated with the corresponding regimens. Meanwhile, the 5th, 6th, 7th, 8th and 9th groups were treated with regimens 2 and 4; 3 and 4; 5; 2 and 6 and 3 and 6 respectively. Our results indicated that irrespective of treatment regimens, a higher pregnancy rate (56.36%) was observed in lactating than in barren mares (50.0%). Regarding the effect of regimen irre- spective of types of mares, a higher pregnancy rate was found in groups 3 (71.40%) and 9 (71.72%) which were treated with regimens 3 and 3 and 6 respectively. It is worthy to note that the lowest value (36.36%) was recorded in group 4 and 7 which were treated with antibiotics alone and oxytocin alone respectively. In conclusion, the intrauterine infusion of leuckocyte enriched homologus plasma alone or with I.V injection of oxytocin increased the pregnancy rate in barren and lactating mares respectively.