The nucleotide sequence of a 799 bp fragment of Mycobacterium bovis BCG containing the putative upp gene that encodes a uracil phosphoribosyltransferase (UPRTase [EC 2.4.2.9]) has been determined. The upp gene of BCG has an open reading frame (ORF) of 621 bp (207 amino acids) starting with GTG (position 112) and ending with TGA (position 733), and its molecular mass was calculated to be 21,864 Da. Comparative analyses of the deduced amino acid sequence of BCG UPRTase with the UPRTase of six bacterial genera revealed that 24% (50/211) of the residues are perfectly conserved and 32% (67/211) of the residues are well conserved.