A 17-year-old man presented with right hydrocele because of an athletic injury. His scrotum was hit with a ball 2 months ago while playing baseball. He was diagnosed with post-traumatic hydrocele and underwent needle puncture at another hospital 1 month after the trauma. However, the hydrocele did not improve. Therefore, he was referred to our hospital for surgical treatment. For diagnosis of the traumatic hydrocele testis, a hydrocelectomy was scheduled. When we opened the tunica vaginalis, we realized that the tunica albuginea had been ruptured and the testicular parenchyma had gushed out. We tried to replace all the escaped testicular parenchyma into the tunica albuginea, but it was impossible. Therefore were moved some of the redundant testicular parenchyma, and replaced the remnants into the tunica albuginea. After the operation, right hydrocele and testicular atrophy did not occur. Traumatic testicular rupture complicated with hydrocele is rare.