The present study aimed to investigate the effect of Rhipicicephalus sanguineus and Babesia species on the fertility of German shepherd dogs, 80 dogs (41 male and 39 female) were examined in veterinary clinics of Mansoura city and Sinbillawain, Dakahlia Governorate aged from 2-3 years during summer and autumn seasons 2021.Twenty-one dogs (26.5%) were infested with Rhipicephalus sanguineus (brown dog ticks) with different degree of infestation and higher prevalence in male dogs (29.2%) than female(23%). While 12 dogs (15%) showed signs of fever, anorexia, pale mucous membrane, weakness and increase in heart rate, examining of thin blood films indicated infection with Babesia spp. with percentage (17%) and (12.8%) in male and female dogs respectively. Biochemical laboratory examinations were done for estimation of testosterone hormone in male and progesterone hormone in female dogs in the estrus phase to detect the effect of external and blood parasites on their fertility. Laboratory findings of testosterone levels in male infested with Rhipicephalus sanguineus ranged from (2.01- 3.2 ng/ml), while others infected with ticks and Babesia spp. showed significant decrease in the testosterone levels in male (0.75 – 1.35 ng/ml). Testosterone levels in apparently healthy male dogs that free from ticks and Babasia spp. ranged from (3.04-4.1 ng/ml). Progesterone levels in bitches infested with Rhipicephalus sanguineus ranged from (2.5-3.4 ng/ml) and (0.2 -0.79 ng/ml) for bitches infested with ticks and Babesia spp., while progesterone levels in bitches free from ticks and Babesia spp. were (2.9-3.4 ng/ml). These results indicate that infestation with ticks (Rhipicephalus sanguineus) only had little effect on the fertility of German Shepherd dogs but when more persistence of ticks with presence of babesiosis can affect their fertility.