Using RT-PCR, a cDNA encoding tomato (Lycopersicon esculentum) ACC oxidase has partially been cloned, sequenced and identified. The nucleotide suquence of the clone was in the coding region and shared about 80% of homology iwht the other ACC oxidase genes of tomato, and 70∼84% with those of other plants such as Oryza sativa, Nicotiana tabacum and Helianthus annuus. In the wounded tomato leaves, this nucleotide transcripts were accumulated rapidly and declined slowly thereafter. These results suggested that the predicted clone might be another member of tomato ACC oxidase gene family.