Eighteen patients were reviewed 7 to 23 years after prolonged unilateral testicular torsion. They had all undergone surgical untwisting with replacement of the nonviable testis in the scrotum during prepubertal period. Five patients were now married and had fathered one or more children. Thirteen patients were unmarried. There was absence of testis on the affected side in 14 of 18 patients. Four patients had severe testicular atrophy on the affected side (testicular volume less than 1 mL). The contralateral side showed either a normal testicular volume or a compensatory hypertrophy (testicular volume greater than 25 mL). Seminal analysis was done in 13 unmarried men and it was completely normal in 10 patients. Two patients had low sperm density but normal semen volume and motility. One patient had pathologic semen analysis. IgG and IgA specific mixed agglutination reaction (MAR) test did not show evidence of sperm autoantibodies in any patient. Our clinical experience shows that, after prepubertal torsion, the contralateral testis undergoes normal development. Furthermore, torsion in the prepubertal male does not cause autosensitization and diminished fertility in adult life.