We have cloned and characterized a gene for squalene synthase (SQS) from Centella asiatica (L.) Urban, a species that produces a large quantity of triterpene saponins such as asiaticoside and madecassoside. Its full-length cDNA clone was isolated by RACE PCR. The sequence of pSQS contains an open reading frame of 1248 nucleotides, which code for 416 amino acids with a molecular mass of 47.3 kDa. Southern analysis revealed that one copy might exist in the C. asiatica genome. We also determined that 0.1 mM methyl jasmonate was sufficient to up-regulate those levels of CaSQS mRNA.