With the assumption that infertility and related diagnostic and therapeutic processes are stressful, an uncontrolled pilot study was designed to evaluate the effect of sildenafil citrate on sexual compliance and reproductive outcome. A group of sexually healthy men were studied after the administration of 50 mg sildenafil before semen collection for intrauterine artificial insemination (n = 25) or planned intercourse for a postcoital test (n = 12). We demonstrated that sexual dysfunction is highly prevalent in patients undergoing diagnostic procedures for infertility, and that sildenafil is effective in reversing stress-induced transitory impotence. Furthermore, sildenafil improved some seminal parameters, such as the percentage of spermatozoa with linear progressive motility, as well as the number of spermatozoa penetrating the cervical mucus. Two pregnancies were obtained after sildenafil administration.