Polymerase chain reaction (PCR) is an oft-used preparatory technique in amplifying specific DNA regions for downstream analysis. The size of an amplicon was initially limited by errors in nucleotide polymerization and template deterioration during thermal cycling. A variant of PCR, designated long-range PCR, was devised to counter these drawbacks and enable the amplification of large fragments exceeding a few kb. In this chapter we describe a protocol for long-range PCR, which we have adopted to obtain products of 6.6, 7.2, 13, and 20 kb from human genomic DNA samples.