The nucleotide scquence of tRNAphe gene of Carp mitochondria was determined. Sequence comparisons made among Whale,Human,Xenopus laevis, Bovine, Mouse,Chicken and Carp revealed a novel conservative structure in the D. stem (dihydrouridine stem),which is known to vary in other vertebrate mitochondrial and eytoplasmic tRNA genes.This conservative structure contains 13 bp. When the first 7 bp of the conserviative structure were compared with the A domain recognized by RNA Pol III, we noticed partial homology between these two kinds of sequences among different species. In view of the tRNAphe gene's close position to the D loop,it is reasonable to expect extraordinary functions in this novel conservation structure.