Genetic diversity has to be described and measured in order to establish breeding strategies and manage genetic resources. It is also fundamental to develop a comparative intraspecific study before attempting to discuss and conclude any phylogenetic relationship. The genetic variability of Lycopersicon species was studied using starch gel electrophoresis of 11 enzymatic systems in a hierarchical fashion. The species with the greatest genetic variability are L. chilense, L. peruvianum and L. pennellii, mainly due to the within-line component. L. chmielewskii, L. parviflorum and L. pimpinellifolium show an intermediate total variability and their between-component clearly predominates over the within-component. The least variable species are L. cheesmanii and L. esculentum. Cluster analysis resulted in three main groups: one formed by the cultigen, L. pimpinellifolium, L. cheesmanii and L. peruvianum;another by two species with self-incompatibility systems, L. pennelli and L. chilense; and another by two autogamous species L. chmielewskii and L. parviflorum. With respect to L. esculentum the farthest related species is Solanum rickii and the closest, L. pimpinellifolium.