We have isolated two types of human P2Y1 cDNA clones from the human erythro leukemia cell cDNA library. The sequence of both clones codes for the same 373 amino acid polypeptide and these clones differ only in the length of the 3' untranslated region. The long form of the cDNA has 1165 nt 3' untranslated region while the 3' untranslated region in the short form is only 258 nt. Both forms are, however, polyadenylated. A multiple human tissue northern blot indicated two transcripts of approximately 4.4 kb and 7.0 kb. The 4.4 kb mRNA is present in all the eight tissues, while the approximately 7.0 kb transcript is expressed only in placenta, skeletal muscle, and pancreas. Using oligonucleotide primers specific for the human P2Y1 purinergic receptor to amplify a region from genomic DNA from a panel of mouse/human somatic cell hybrid cell lines, we have localized the P2Y1 gene to human chromosome 3.