Pseudochorthippus parallelus parallelus (Zetterstedt, 1821) (Orthoptera, Acrididae) is a widespread species in Europe, and also it is localized in some regions in Turkey such as Bursa, Eskisehir, Ankara, Bolu, Duzce, and cankiri. The features of the reproductive organs such as the numbers and shapes of testes and follicles can be used as taxonomical characters. For this purpose, the ultrastructural and histological features of testis and vas deferens in P. parallelus parallelus were examined with using light microscope, scanning electron microscope, and transmission electron microscope. The mature P. parallelus parallelus has two conjugated testes produce spermatozoa. Each testis is composed of numerous testis follicles in which different stages of spermatogenesis and spermiogenesis develop. First, spermatocytes are formed by the mitosis division of the germ cells at the distal end of the follicles. Then, spermatocytes form spermatids by meiosis division in the middle region of the follicles. Finally, spermatids are differentiated to spermatozoa at the proximal region of the follicles. After maturation of the spermatozoa, sperm tails come together as the sperm bundles called as spermatodesm. Each follicle is connected to vas deferens via vas efferens to discharging spermatozoa. In spite of some differences, the testes and the vas deferens in P. parallelus parallelus are highly similar to the those of other species, especially Orthopteran species.