Nasturtium is a plant in the family Trapaeolaceae cultivated in Europe, Asia, Africa, and America, which has numerous healing, antiseptic, and expectorant activities.  It is the most important herbal medicine used for curing some diseases like diabetes, bronchitis, cardiovascular disorders, and urinary tract infections. There are many chemical constituents isolated from Nasturtium including polyphenols, glucosilonates and fatty acids. Many systems of the body like the reproductive system are affected by some herbal plants, which contain essential chemical active substances with biological properties. The present study was conducted to investigate the effect of hydroethanolic extract of Nasturtium on parameters of reproductive and sex hormones on male rats. Sixty mature male albino rats weighing 180-200 g were divided into three equal groups at random. The first group was kept as a monitor and consisted of 20 rats that were given distilled water daily for 30 days. The second group consisted of 20 rats, which were given hydroethanolic  extract of Nasturtium flowers orally via a stomach tube at a dose of 250 mg/kg body weight (BW.), and the third group consisted of 20 rats, those were given hydro-alcoholic extract of Nasturtium leaves every day for four weeks. Blood samples were collected from all rats to estimate serum levels of luteinizing hormone (LH) and follicular stimulating hormone (FSH), testosterone and prolactin. The testicles, seminal vesicles and prostate glands were weighted and the sperms were collected from the epididymis to calculate the sperm count. The results showed decreased testosterone level in flower extract (1.10 ± 0.238) and leaves extract (0.89 ± 0.08) compared to the control group (3.75 ± 0.35).  Also, LH decreased in flower extract (0.225 ± 0.025) and leave extract (0.103 ± 0.003) compared to the control group (0.105 ± 0.003). Meanwhile, serum FSH level in flower extract (0.60 ± 0.07)and leaves extract (0.45 ± 0.05) showed non-significant change compared with the control group (0.35 ± 0.029). The fast mobility of sperm indicated non-significant change compared with the control group. In conclusion, hydroethanolic extract of Nasturtium make attributed levels on sex hormones, which give negative effect on fertility despite of its chemical compounds.