The effects of chemical sympathectomy on contralateral testicular histology, fertility and fecundity following unilateral testicular torsion were evaluated in rats. Four groups, placebo plus sham operation, 6-OH-dopamine plus sham operation, placebo plus torsion, and 6-OH-dopamine plus torsion, were established. When the placebo plus sham operation and placebo plus torsion groups were compared, it was found that contralateral testicular damage following unilateral testicular torsion occurred with significantly decreased values for mean seminiferous tubular diameter (MSTD), mean testicular biopsy score (MTBS) and fertility. The relatively normal values for MSTD, MTBS and fertility in the 6-OH-dopamine plus sham operation and 6-OH-dopamine plus torsion groups indicate the preventive role of chemical sympathectomy on contralateral testicular damage. Since chemical sympathectomy prevents contralateral histologic deterioration and preserves fertility in unilateral testicular torsion, the decreased blood flow in the reflex-activating sympathetic system may play a role in contralateral testicular damage.