Kisspeptin-54 is a neuropeptide encoded with Kiss-1 gene which signal by G protein receptors. It has an essential role in controlling reproductive axis by inducing hypothalamic gonadotropin-releasing hormone which in turn induce adenohypophyseal gonadotropins with subsequent stimulation of sex hormones and gamete development from the gonads. Aim: to investigate the effects of prolonged continuous peripheral subcutaneous injection of kisspeptin-54 by use of Alzet miniosmoticpumps on blood levels of LH, FSH, testosterone, testis weight, count and motility of sperms in adult male rats. Material and Methods: two groups of adult male rats (ten rats for each group) were used in the experiments to investigate the results of subcutaneous administration of kisspeptin-54 for 13 days using Alzet miniosmoticpumps implanted subcutaneously in the interscapular region to guarantee continuous delivery of Kisspeptin-54 throughout the study (50 nmol/day). Results: the study results showed that prolonged injection of kisspeptin-54 at a dose of 50 nmol/day for thirteen days in male rats decreased significantly blood level of LH, FSH, testosterone (P < 0.001) and testis weight, sperm count and motility (P < 0.001). Conclusion: it can be concluded that chronic, prolonged and continuous subcutaneous administration of Kisspeptin-54 may affect male fertility by causing significant decrease in testicular weight and sperm viability, count and motility through direct desensitization of hypothalamic–pituitary–gonadal axis rather than direct inhibitory effect on the gonads.