A low temperature-inducible cDNA designated as VrUBC1 from mungbean (Vigna radiata) was isolated by subtractive hybridization method. By rapid amplification of cDNA end technique, the full-length cDNA of VrUBC1 was obtained. The full-length cDNA of VrUBC1 contains an open reading frame of 444 nucleotides in length and capable of specifying a 16.5-kDa protein of 148 amino acids (aa) with an isoelectric point of 7.72. VrUBC1 mRNA was induced by NaCl and ABA, but not by wounding and low temperature stress. It was shown that VrUBC1-GFP was localized to the cytoplasm in tobacco cell. To examine the function of VrUBC1, VrUBC1 was expressed in Escherichia coli as His-fusion protein. Purified VrUBC1-His recombinant protein was shown to have ubiquitination activity in vitro. For the in vivo functional analysis of VrUBC1, VrUBC1 was expressed in yeast ubc4/5 double mutant. Stress tolerance was tested in the VrUBC1 overexpressing Arabidopsis transgenic plants. We propose that VrUBC1 play an important role in protein degradation processes during abiotic stress in plants.