The aim of this study was to evaluate the concentration and chemical composition of the essential oil the leaves of basil cultivars and hybrids cultivated in different cropping seasons: dry season and rainy season. The variables evaluated were the content and composition of essential oils in the two seasons. The essential oil content ranged from 0.66% to 3.21% in the dry season and from 0.80% to 4.20% in the rainy season. The major compounds found among the genotypes were linalool, methyl chavicol, neral, geranial, eugenol, and methyl (E)- cinnamate, defining the formation of five groups in each season, classified in the following chemotypes: methyl chavicol (Group 1), citral (neral+geranial) (Group 2), methyl cinnamate (Group 3), linalool (Group 4), and intermediate linalool (Group 5). All the traits evaluated had heritability (h ) greater than 95% and high CVg/CVe ratio values. The cropping season affected the content and chemical compositions of basil essential oil.