The human chromosome complement of somatic cell hybrids must be assessed each time the hybrids are grown in culture. We have developed a panel of human-specific oligonucleotide primers for genes that have been mapped to each of the autosomes and to the X chromosome. These primers enable the human chromosome content of hybrids to be assessed rapidly by PCR. The sequence of the primers is presented together with the appropriate conditions for human DNA-specific amplification for each pair.