We present the sequences of a set of oligonucleotides that, when used as primers for PRimed IN Situ (PRINS) labeling, are diagnostic for repetitive sequences in specific human chromosomes. Combined, they enable identification of all human chromosomes except 6, 19, and 20. However, as is also the case with cloned centromeric hybridization probes, chromosomes 14 and 22 are stained together. Along with the sequences of these oligonucleotides we offer a simple, universal procedures for their use. We also present an oligonucleotide that binds to both strands of alpha-satellite DNA, making it possible to specifically amplify alpha-satellite DNA by PCR with this one oligonucleotide alone as primer. The origin of the alpha-satellite DNA in the starting material (whether somatic cell hybrids, flow-sorted chromosomes, or microdissected material) can then be determined on test metaphase spreads by in situ hybridization or PRINS with the PCR product.