The ras gene plays an important role in signal transduction in eukaryotes. Isolation of ras or ras-related gene from Nicotiana tabacum was attempted. Genomic DNA was screened with human c-Ha-ras as a probe and 15 positive clones were obtained. Each clone was classified into three subgroups according to its signal intensity and three clones were selected from each group. DNA was purified from those clones and digested with many types of restriction endonucleases. Southern analysis was carried out and three DNA fragments of group I and II which showed positive signal was subcloned into cloning-sequencing vector, pBluscriptIIKS+. Cloned DNA fragments were restricton endonuclease mapped.