Hydrocele is generally believed as innocent. But there is increasing evidence of noxious influences of hydrocele on testis resulting in morphological, structural and functional consequences. These effects are due to increased intrascrotal pressure and higher temperature-exposure of the testis. Increased intrascrotal pressure can cause testicular dysmorphism and even testicular atrophy. The testicular dysmorphism is reversible by early hydrocele surgery, but when persist, possibly indicate negative influence on future spermatogenesis. Spermatic cord compression by hydrocele is responsible for testicular volume increase. Such testes lose 15%-21% volume after hydrocele surgery. Tense scrotal hydrocele can cause acute scrotal pain from testicular compartment syndrome, which is relieved by evacuation of hydrocele. Higher resistivity index of subcapsular artery of testis and higher elasticity index of testicular tissue are caused by large hydrocele. As an aftermath, testis suffers ischaemia with long-term effect on spermatogenesis. High pressure of hydrocele along with ischaemia and oedema is found to result in histopathological damage to testis like total/partial arrest of spermatogenesis, small seminiferous tubules, disorganized spermatogenetic cells, basement membrane thickening and low fertilty index in children. Higher temperature exposure of testis interferes with spermatogenesis. In adults it results in lower quality of semen in the form of oligospermia and low motility of sperms. Congenital hydrocele can be observed upto 2 y age and noncongenital hydrocele upto 1y period for spontaneous resolution in the absence of associated pathology indicating earlier operation like inguinal hernia, cryptorchidism, tense hydrocele, testicular torsion, testicular mass,etc. In adults with tense hydrocele early operation is indicated.