Members of the PIAS (protein inhibitor of activated STAT) family perform essential functions in modulating the activity of transcriptional regulators. Zimp7 and Zimp10 are two proteins that together form a subfamily of the PIAS. Like the other members of this family, they contain the zinc-binding SP-RING/Miz domain, which confers SUMO-conjugating activity. Both proteins have been shown to stimulate androgen receptor-mediated transcription. Previously, we reported that both Zimp7 and Zimp10 genes are extensively expressed and dynamically regulated in the developing mouse embryo. In this work, we investigated the expression of these genes during gonadal development. We found that their expression is sex-specific. Both genes initiate their transcription at early stages in the embryonic male gonad, reaching their peak at 13.5days post coitum, which coincides with the process of sex-specific germ cell mitotic arrest. Zimp7 is expressed in germ cells of the embryonic gonad and the adult testis. Immunofluorescence of spermatogenic cells revealed that Zimp7 protein localizes to nuclear territories in meiotic spermatocytes, including the XY bodies. On the other hand, Zimp10 is found in somatic cells, outside the testis cords and ceases to be expressed in the adult testis.