Analysis of DNA variation in biological samples most frequently utilizes the polymerase chain reaction (PCR) performed on extracted genomic DNA, followed by visualization of alleles using various methodologies. Few reports have demonstrated that amplification of DNA from plasma and serum samples is possible. We have performed DNA amplification on a large set of serum samples (n = 2955). Here, we report that known hereditary mutations in the BRCA gene can efficiently be analyzed in serum samples collected and stored over several decades. Fragments were PCR-amplified following a short initial denaturation of the serum sample in a standard microwave oven. Fragment analysis was subsequently performed using a DNA capillary-sequencing instrument. The PCR success rates were fragment- and size-dependent ranging from 83.2% to 97.9%. Of the 11,820 polymerase chain reactions performed, the overall PCR success rate was 91.3% (10,796/11,820), which is comparable to PCR performed on genomic DNA. The advantage of the method described herein is its ability to utilize archival material stored in serum biobanks for long periods of time.