The mRNA differential display technique was used to compare mRNA populations from fruit body and mycelium of a white truffle species in the attempt to identify and clone differentially expressed genes. The differential expression of five out of 30 amplicons was confirmed. One fragment (Tbm 56) corresponded to a part of the ribosomal genes. Three cDNA fragments (Tbf 12, Tbf 20, Tbf 21) were expressed only in the fructification phase, while the other cDNA (Tbf 55) was expressed strongly in fruit body and also detectable in the mycelium. These clones correspond to part of the single-copy genes in the Tuber borchii Vittad. genome.