A total number of 74 mares of Thoroughbred-Arabian cross breed, 3-5 years old, with problems of infertility, were clinically identified and classified into three groups. Following the only rectal massage for ovaries and uterus (subnormol group, 14 cases), administration of PGF2-Alpha (Subestrous group, 40 cases) and FSH, PGF2-Alphs and LH (Anestrous group, 20 cases). The rates of sexual response were 100, 72.50 and 75.00%, the rates of pregnancy were 78.57, 75.86 and 80.00% and the numbers of services per ocnception were 1.28 +0.12, 1.83 +0.13 and 1.56 +0.18 for the three groups, respectively. The present study indicated that fertility of mares is mainly improved by care attention during the breeding season.