RNAs that function in mitochondria, in contrast to the majority of mitochondrial proteins, are generally encoded by the mitochondrial genome. However, evidence has been presented for transport of nucleus-encoded tRNAs into mitochondria in diverse organisms. While mitochondrial protein import has been characterized in great detail, virtually nothing is known about the pathway of RNA import into mitochondria. Only very recently have in vivo systems for RNA import been established, and these are now providing some insight into this intriguing process.