Ashwagandha (Withania somnifera) has been described in traditional Indian Ayurvedic medicine as an aphrodisiac that can be used to treat male sexual dysfunction and infertility. This pilot study was conducted to evaluate the spermatogenic activity of Ashwagandha root extract in oligospermic patients. Forty-six male patients with oligospermia (sperm count < 20 million/mL semen) were enrolled and randomized either to treatment (n = 21) with a full-spectrum root extract of Ashwagandha (675 mg/d in three doses for 90 days) or to placebo (n = 25) in the same protocol. Semen parameters and serum hormone levels were estimated at the end of 90-day treatment. There was a 167% increase in sperm count (9.59 ± 4.37 × 106/mL to 25.61 ± 8.6 × 106/mL; P < 0.0001), 53% increase in semen volume (1.74 ± 0.58 mL to 2.76 ± 0.60 mL; P < 0.0001), and 57% increase in sperm motility (18.62 ± 6.11% to 29.19 ± 6.31%; P < 0.0001) on day 90 from baseline. The improvement in these parameters was minimal in the placebo-treated group. Furthermore, a significantly greater improvement and regulation were observed in serum hormone levels with the Ashwagandha treatment as compared to the placebo. The present study adds to the evidence on the therapeutic value of Ashwagandha (Withania somnifera), as attributed in Ayurveda for the treatment of oligospermia leading to infertility.