Acute epididymo-orchitis caused by Pseudomonas aeruginosa is relatively unusual but difficult to treat, especially in the elderly. We report three cases involving P. aeruginosa all of which concerned patients with preexisting genito-urinary disease. The properties of ciprofloxacin make it suitable for the treatment of this condition. Its use was followed by clinical cure in all three patients and eradication of P. aeruginosa in two of them.