Emerging evidence indicates that mitochondrial carriers are not only crucial for metabolism, but also important for embryonic development. Sideroflexin is a novel family of mitochondrial tricarboxylate carrier proteins, of which the in vivo function is largely unknown. Here, we report on the expression patterns of five sideroflexin genes in Xenopus embryos. Whole-mount in situ hybridization analysis reveals that while sideroflexin2 is expressed in the pancreas, sideroflexin1 and 3 display a complex expression in the central nervous system, somites, pronephros, liver, and pancreas. In contrast, only a weak expression of sideroflexin4 and 5 was detected in embryonic brain. Taken together, the five sideroflexin genes show both overlapping and nonoverlapping expression during Xenopus embryogenesis. As the primary structures of the five sideroflexin proteins are also quite similar, their functional redundancy should be taken into consideration for gene targeting studies.