The PreCR® Repair Mix is an enzyme cocktail formulated to repair damaged template DNA prior to its use in the polymerase chain reaction (PCR), microarrays or other DNA technologies. PreCR is active on a broad range of DNA damages, including those that block PCR (e.g. apurinic/apyrimidinic sites, thymine dimers, nicks and gaps) and those that are mutagenic (e.g. deaminated cytosine and 8-oxo-guanine). In addition, it will remove a variety of moieties from the 3´end of DNA leaving a hydroxyl group. The PreCR Repair Mix will not repair all damages that inhibit/interfere with PCR. For example, it will not repair 8-oxo-7,8-dihydro-2’deoxyadenosines or fragmented DNA. In fact, the ligase present in the mix is very active at sealing nicks in DNA but does not ligate blunt ends or nicks near a mismatch effectively. This limits the possibility of chimeric gene formation as a product of ligation. The PreCR Repair Mix can be used in conjunction with any thermophilic polymerase.