A full-length cDNA, named LeEIN2 was cloned from tomato (Lycopersicon esculentum) by RT-PCR and RACE. Then the genomic DNA sequence of Le EIN2 was isolated by LA (Long and Accurate) PCR and Inverse PCR. This DNA sequence was 6838 bp including six introns. The Le EIN2 cDNA was 4343 bp and contained a 3951 bp open reading frame, encoding a 142.63 kDa protein of 1316 amino acids. Comparison of this protein sequence with that of Arabidopsis and Petunia showed that the amino acid homology was 66 and 90%, respectively. Northern blotting analysis indicated that the expression level of the LeEIN2 in young leaves was higher than in mature leaves and senescent leaves. During the development of fruits, the expression of the Le EIN2 was detected before mature green stage and got up to maximum at mature green and breaker stages, then reduced rapidly after breaker stage. The expression level of LeEIN2 in wild type tomato fruit at mature green stage did not distinctively change when treated with exogenous ethylene.