The Quantitative PCR Primer Database (QPPD) provides information about primers and probes that can be used to quantitate human and mouse mRNA by reverse transcription polymerase chain reaction (RT–PCR) assays. All data has been gathered from published articles, cited in PubMed. Searching in the QPPD you will find: primer sets and probes for a given gene, primer location, amplicon size, assay type, positions of single nucleotide polymorphisms (SNPs), literature references, available I.M.A.G.E. cDNA clones, the Primer Viewer, a graphical representation of the gene and primer sets, which includes hyperlinks to Gene Info from the Cancer Gene Anatomy Project (CGAP) and the CGAP SNP viewer. Registration not required.