The plant Juniperus phoenica (L.) (Cupressaceae) is widely growing on the rocky soils of the Mediterranean regions. In Jordan, the plant is distributed in different locations and is used as a folk medicine to treat rheumatism, edema, and urinary tract diseases. This study aimed to investigate the antifertility effect of J. phoenica in male albino rats. Animals were administered single daily intraperitoneal injections of 400 or 800 mg/kg of J. phoenica cones ethanol extract or the vehicle (dimethyl sulfoxide) for 21 consecutive days. A marked dose-dependent decrease in the counts and motility of the sperms collected from the cauda epididymis of treated rats was observed compared with the control. Furthermore, pregnancy rate in females markedly reduced by 60% and 80% after mating with males treated with 400 or 800 mg/kg, respectively. At the same time, significant decreases were detected in seminal vesicles and testicular weight of rats that received 800 mg/kg as compared with control rats. Testosterone levels were decreased significantly in both treated groups as compared with control. Histologically, seminiferous tubules of treated rats showed marked arrests of spermatogenesis and a marked decrease in the number of mature sperms. Therefore, the results of this study suggest that the ethanolic extract of the cones of J. phoenica possesses potential antifertility effects.