Chronic prostatitis (CP) due to Chlamydia trachomatis (Ct) infection has a significant impact on young male fertility, and eradication of Ct infection after antibiotic therapy does not always result in recovery of semen quality. The study aim was to evaluate the effects on fertility parameters of L-arginine, Lcarnitine, acetyl-L-carnitine, and ginseng extracts (FERTIMEV) associated with prulifloxacin in patients affected by CP and oligoasthenoteratozoospermia due to Ct infection. Two hundred and six patients with proven Ct genital infection and oligoasthenoteratozoospermia were enrolled in a prospective, randomized, and controlled study. Prulifloxacin (600 mg) was administered daily for 14 days, and patients were divided into 2 groups: group A: antibiotic therapy alone; and group B: antibiotic therapy and additional therapy with FERTIMEV (1 vial daily for 6 months). Microbiological and semen parameter analyses were performed both at enrollment and after 6 months. National Institutes of Health Chronic Prostatitis Symptom Index and International Prostatic Symptom Score questionnaires were applied. Of the 206 patients, 109 were assigned to group A and 97 to group B. At the enrollment time, no differences were reported with regard to clinical, instrumental, and laboratory data. Six months after treatment, statistically significant differences were demonstrated between both groups in terms of sperm concentration (21.3 6 13.2 millions/ mL vs 11.5 6 13.2 millions/mL) (Cohen's d 5 0.61) (P , .001, df 5 2, F 5 62.10) and percentage of motile sperm (42.4% 6 5.2% vs 29.3% 6 11.0%) (Cohen's d 5 1.52) (P , .001, df 5 2, F 5 91.48). In this study treatment with FERTIMEV together with prulifloxacin improved semen parameters in patients with Ct genital infection and oligoasthenoteratozoospermia compared to treatment with prulifloxacin therapy alone.