Quinolones, elective drugs for Pseudomonas aeruginosa (P. aeruginosa) pulmonary infections in Cystic Fibrosis (C.F.) patients, are controversially administered in prepuberal age for their arthropathic toxicity. We report the result of retrospective study on the use of quinolones in a group of 43 CF patients. The patients were divided into two groups: below 18 years (22 pts.) and over 18 (21 pts.). All patients were evaluated clinically with the scoring system Shwachman and Kulczyk. Ciprofloxacin and Ofloxacin (15/20 mg/kg/die) were administered. In 11.6% of the patients, all belonging to the second group, side effects, such as urticaria, tongue oedema, foreskin erythema, generalised erythema and itch, were described. No side effect has been reported in the patients below 18 years. Two patients complained knee arthralgias not related to the quinolones administration: in fact in the first case the demineralisation seemed to be responsible of the arthralgia, while in the second case an immunological disorder (ANA+, ICC+) should be involved in the pathogenesis of arthritis. Height velocity evaluation showed the same slowering of the CF untreated patients. In conclusion, our study confirms that quinolones use in indicated in severe and infective complications of CF on the basis of their efficacy, safety and their slight adverse effects similar to those of other potent antibiotic. Moreover our results confirm that no quinolone-induced cartilage toxicity is present in CF patients.