Aim: In SD rats, histological changes in the testis were observed after bilateral capsulotomy (of the tunica albug-inea) in order to investigate the physiological role of the testicular capsule on sperm transport. Methods: Bilaterallongitudinal capsulotomy was devised to disrupt the capsular contractile function. With this technique, only the tunicavaginalis and tunica albuginea were slit open, leaving the tunica vasculosa intact to embrace the underlying testicularparenchyma. After capsulotomy, the structural changes in the seminiferous tubules, the transitional distal seminiferoussegment, and the rete testis were observed. Results: In the capsulotomized testis, there was sperm retention at thetransitional seminiferous segment and progressive degenerative changes in seminiferous tubules. Conclusion: Theresults clearly indicated that an intact testicular capsule was required for normal sperm transport from the seminiferoustubules into the rete testis. This is the first attempt to study the physiological Aim: In SD rats, histological changes in the testis were observed after bilateral capsulotomy (of the tunica albug-inea) in order to investigate the physiological role of the testicular capsule on sperm transport. Methods: Bilaterallongitudinal capsulotomy was devised to disrupt the capsular contractile With this technique, only the tunicavaginalis and tunica albuginea were slit open, leaving the tunica vasculosa intact to embrace the underlying testicular parenchyma. After capsulotomy, the structural changes in the seminiferous tubules, the transitional distal seminiferous segment, and the rete testis were observed. Results: In the capsulotomized testis, there was sperm retention at the transmisal seminiferous segment and progressive degenerative changes in seminiferous tubules. Conclusion: Theresults clearly indicated that an intact testicular capsule was required for normal sperm transport from the seminiferoustubules into the rete testis. This is the first attempt to study the physiological