Compartmentalization of human cytosolic malate dehydrogenase, hcMDH, together with its isozyme partner-mitochondrial form, hmMDH, plays an important role in the aerobic metabolism of the malate-aspartate shuttle and the citric acid cycle. However, they share few structural homology at the molecular level. The pseudogenes of mMDH has been reported in mice but hcMDH has no pseudogenes as shown by Southern blot analysis. A single band only was detected for the EcoRI digestion with 9.4 kb long of human genomic DNA and HindIII cutting with 2.8 kb long. hcMDH gene was mapped to chromosome 2 by somatic cell hybrid analysis and further localised to 268.72 cR from the top telomere of Chromosome 2 (near 2p15) by radiation hybrid mapping. The genes falling into this region may be related to dilated cardiomyopathy (DCM), several types of cancers and immunoregulation mechanism of cancers.