In order to identify DNA variants potentially involved in the regulation of the expression of the bovine growth hormone gene, the 5'-flanking, the 5'-untranslated and the signal peptide coding regions of 15 cows (four German Friesian, two German Simmental, two Jersey, two Galloway, two Scottish Highland, two Charolais and one Ceylon Dwarf Zebu) were analysed. For each animal a region of about 1.2 kb was amplified by polymerase chain reaction (PCR) and sequenced. Six sites of variable nucleotides were identified in the 5'-flanking region of the gene and one in the intron I. Some of these variable sites are also potential binding sites for trans-acting factors (CAAT/enhancer binding protein (C/EBP), polyoma virus enhancer A binding protein 3 (PEA3), thyroid hormone response element (TRE)) and therefore possibly involved in the expression of the growth hormone gene. PCR amplification of specific alleles (PASA) tests for two of the sites (G2, G3) were established and the genotypes for these variants were analysed in 190 cows. The frequencies of the C alleles of the sites G2 and G3 were 0.63 and 0.76, respectively.