Since publication of the article, "tRNAs and Proteins Are Imported into Mitochondria of Trypanosoma brucei by Two Distinct Mechanisms," by C. E. Nabholz, E. K. Horn, and A. Schneider (Mol. Biol. Cell [1999] 10, 2547-2557), the authors discovered that the standard substrate that was used in the described import assays was heterogeneous. It contained prematurely terminated transcripts of 8 and 12 nucleotides. The authors were able to show that these small fragments are selectively imported into mitochondria, whereas the intact tRNA is not. After import, these small RNAs are converted into the two sets of RNase-resistant fragments by a ligation-type event. All conclusions reported in the original paper remain valid but apply only for the short RNA fragments and not for the original transcript as claimed.