It is expected that in triploid organisms the energy normally used for reproduction would be allocated to growth. However, not all triploid molluscs are completely sterile, and in some cases even gametes are produced. The aim of this study is to assess the gonadal development in the native scallop Argopecten purpuratus induced to triploidy. Argopecten purpuratus Lamarck 1819, is a functional hermaphrodite, the male portion of the gonad being creamy-white, located proximal to the foot, and the distal female gonadal portion is bright orange-red. They were induced to triploidy with 6-dimethylaminopurine (6-DMAP). Treated (=induced) and control scallops were processed for histology using routine methods. At the age of 11 mo, when the control scallops were mature, some treated scallops had a gonad, which showed a uniform brown color. These were true triploids, assessed by chromosome counts. They showed the tendency of reducing the “ripeness” of the female gonad, only few acini with oocytes were observed, associated to hemocytes, presumably phagocytosing them. Female acini were mostly empty. The male gonad was relatively more developed, but the spermatocytes, spermatids and spermatozoan-like cells showed a highly abnormal morphology. This evidence strongly suggests that these gametes are incapable of viable fertilization. Triploid A. purpuratus did not lose their hermaphroditic condition, which was different from another functional hermaphrodite scallop, Argopecten ventricosus, whose triploid gonad turned into only female.