en public specific orginal article <div style="text-align: justify;"><strong>Background: </strong>Animal models and observational studies have suggested a favorable role of vitamin D in male reproduction. However, randomized clinical trials investigating the effect of vitamin D supplementation on male fertility are limited. Therefore, this study aimed to examine the effect of vitamin D supplementation on semen quality, reproductive hormones, and anthropometric measurements in vitamin D deficient males with Asthenozoospermia. <strong>Methods: </strong>Forty-four males with infertility were randomly assigned to the vitamin D group (DG, supplemented with 9 pearls of vitamin D containing 50000 IU vitamin D₃ once a week for 12 weeks) and placebo group (PG, received 9 pearls of placebo once a week for 12 weeks). Semen quality markers (sperm count, morphology, sperm motility, semen volume), total testosterone, sexual hormone binding globulin (SHBG), free androgen index (FAI), and anthropometric measurements (weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), and waist to hip ratio (WHR) were measured at the baseline and the end of the study. <strong>Results: </strong>Serum 25-OH-D levels were significantly higher in the DG compared with the PG. In a multivariate adjusted model, WC significantly decreased in the DG in comparison to the CG (-0.90 &plusmn; 0.67 cm VS 0.49 &plusmn; 0.38 cm). A marginally-significant increase was observed after vitamin D supplementation for SHBG compared to the baseline value in DG (11.69 &plusmn; 5.79, <em>P</em> = 0.05). Compared to the baseline value, sperm immotile was decreased after vitamin D supplementation in the DG (-12.35 &plusmn; 5.13,<em> P</em> = 0.02). However, no statistical significant differences were observed in the semen quality markers (sperm count, morphology, motility, and volume), total testosterone, free androgen index, and other anthropometric values. <strong>Conclusions:</strong> Vitamin D supplementation did not improve semen quality markers, reproductive hormones, and other anthropometric measurements in vitamin D&ndash;deficient infertile men compared to the control group.<br> &nbsp;</div> Vitamin D, Male infertility, Semen quality, Reproductive hormones 31 42 http://jnfs.ssu.ac.ir/browse.php?a_code=A-10-187-1&slc_lang=en&sid=1 Alireza Gheflati 0000-0002-2306-9508 No Department of Nutrition, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Seyed Ali Mohamad Mirjalili 0000-0002-8037-850X No Department of Urology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran Mojtaba Kaviani Kaviani No School of Pure and Applied Science, School of Nutrition and Dietetics, Acadia University, Wolfville, NS, Canada. Amin Salehi-Abargouei 0000-0002-7580-6717 No Department of Nutrition, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Elham Hosseini-Marnani 0000-0003-3724-0166 No Department of Nutrition, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran. Azadeh Nadjarzadeh azadnajarzadeh@ssu.ac.ir 0000-0002-9740-8402 Yes Department of Nutrition, School of Public Health, Shahid Sadoughi University of Medical Sciences, Yazd, Iran