The presence of methyl eugenol in the oil and the difficulty experienced in its separation was considered to be a negative attribute in theCymbopogon flexuosus (var. RRL-59). A mutation breeding programme was initiated to rectify this inherent defect. A massive screening of irradiated vegetative slips of this essential oil-bearing plant resulted in the isolation of a methyl-eugenol deficient mutant. Our results show that once the methyl eugenol is absent from the oil, the oil as such closely resembles the oil of citronella (Java type) and can be a good substitute for the same. This investigation supports the view that beneficial mutations at specific gene loci once isolated in a vegetatively propagated species can be easily stabilised and propagated.