Environmental stresses such as drought, high salinity, cold and heat influence plants growth and productivity. Although these stresses come in various forms, but they cause water deficit stress. Plants respond and adapt to dehydration stresses at physiological and biochemical levels to survive under stress conditions. Molecular studies have shown that several genes with various functions are induced by environmental stresses. These inducible genes function in stress tolerance or regulate signal transduction and gene expression during the stress condition. Expression analyses of dehydration-responsive genes have provided at least four independent regulatory systems (regulons) for gene expression. DREB (dehydration-responsive element-binding protein) is important regulons, which is involved in environmental stresses and classified into, DREB1 and DREB2. The aim of the present study was to overexpress DREB2A and DREB2A-CA (Constitutive active form of DREB2A ) in potato plants to investigate their effects on osmotic tolerance. Two DNA cassettes containing DREB2A and DREB2A-CA cDNA under the control of the CaMV 35S promoter were cloned into a pBI121 plasmid. These construct were transformed into Agrobacterium tumefaciens strain LBA4404 and then transgenic potato ( Solanum tuberosum ) plants were produced using 5 transformation protocol. The present and expression of the gene in the transgenic plants were confirmed with PCR and AT-PCR technique, respectively. The overexpresion of DREB2A-CA increased heat tolerance and caused growth retardation compared with the control transgenic DREB2A plants. In contrast only very weak growth retardation was observed in 35S:DREB2A plants. The increasing tolerance in transgenic potato was showed that there are several genes which response to DREB2A regulon. These results indicate that application of regulon biotechnology can improve stress tolerance in crops such as potato.