We have determined the nucleotide (nt) sequence of a segment of the yeast chromosome carrying the RAD2 gene. The coding region consists of 2925 bp and could encode a protein of 975 amino acids with a calculated Mr of 111 100. A major transcriptional start point was mapped to a position of approx. 22 bp upstream from the first ATG codon. A number of minor transcriptional start points were also identified in this region, all of them 5' to the putative translational start codon. We noted a number of consensus nt sequences in the 5' and 3' non-coding regions of the RAD2, RAD1 and RAD3 genes of Saccharomyces cerevisiae. In addition, three regions of amino acid sequence homology in the putative RAD1 and RAD2 polypeptides were observed.