The advent of direct sequencing of polymerase chain reaction (PCR) products has permitted extremely rapid analysis of DNA mutants and cDNA clones. However, direct PCR sequencing has been problematic for a number of technical reasons, including the presence of impurities and excess oligonucleotide primers used for the PCR amplifications (1 –4 ). Therefore, a number of protocols have been devised that address these technical issues, and allow efficient sequencing of either conventional double-stranded PCR products or asymmetrically amplified single-stranded products (e.g., 1 –4 ). Many of these protocols are described in detail in this volume.