The essential oil composition of 16 populations of Lippia alba collected from all over Guatemala was screened. Fourteen populations belonged to the myrcenone chemotype, containing myrcenone and (Z)-ocimenone as main compounds, while two populations were classified as belonging to the citral chemotype, containing 1,8-cineol, neral and geranial. Additionally, the two morphotypes identified, correlated highly with the chemotypes. This correlation allows a presumption of the existence of two subspecies within Lippia alba in Guatemala. Copyright (C) 2004 John Wiley Sons, Ltd.