A portable evidence preservation system for storing and transporting forensic evidence, in particular items containing blood, fibers, hair, and semen samples, in one or more generally energy-efficient, cool, dry, contaminate-free, isolated chambers. The system includes a housing having a plurality of chambers for storing and transporting forensic evidence therein, an HVAC unit for providing, and desirably recirculating, a supply of air through the chambers and for maintaining the supply of air at a predetermined temperature and at a predetermined humidity. A plurality of HEPA-type filters separately filters the supply of air to each chamber. The cool, dry air in the chambers inhibits and reduces the rate of the growth of bacteria which can destroy DNA and other proteins in the items of evidence containing blood and semen samples. The HEPA-type filters are effective to reduce cross-contamination between items in a chamber and between items in different chambers. The HEPA-type filters are also effective to trap airborne bacteria in the supply of air.