Osmotic stresses are the most important obstacles in growth and development of agricultural and horticultural plants. DREB transcription factors are the most influential regulatory factors which confer plants tolerance against drought, salinity, cold and heat by activating multiple downstream genes, directly or indirectly. Grapevine is an important soft-berry plant in Iran and the whole world, which is prone to yield loss under severe stressful situations. However, despite prediction of some DREB2-type genes in Vitis vinifera , VvDREB2C gene appertaining to this group has not been studied in detail yet. Therefore, in this investigation, the VvDREB2C gene, was isolated and cloned from grapevine genotype ( Vitis vinifera L. ‘Askari’). Further analyses revealed that the 1068 bp cDNA, possesses all the characteristics of DREB transcription factors, namely conserved domains, motifs and residues. Moreover, phylogenetic and motif-based trees depicted that the VvDREB2C is homolog of ArabidopsisDREB2C gene and promoter analysis of the gene predicted several osmotic stress-responding cis-elements, which are also considered as a prerequisite for DREB genes to function. The manipulated VvDREB2C , lacking negative regulatory domain, which is found in some DREB2 s, was constructed using SOEing PCR, and approved by sequencing. In order to study the function of VvDREB2C gene under salt and drought stresses in Petunia plant, pBI121:35S: VvDREB2C construct was made and transformed to Petunia leaf-discs via Agrobacterium . Regenerated transformed Petunia lines, under both salinity and drought stresses, not only showed tolerance in comparison to wild-type lines, but also had higher level of root length, relative water and proline content. In general, VvDREB2C gene from grapevine is a member of DREB2 subfamily that has high potential for being induced by osmotic stresses, and overexpression of VvDREB2C gene in Petunia conferred significant tolerance to transformed plants under salt and drought stresses. Keywords : DREB2 genes, salinity, drought, stress, transcription factor, Vitis vinifera , transgenic Petunia