Among the great Brazilian biodiversity, there are innumerable species of plants that have been traditionally used to treat various diseases. However, great amount of them have not been validated yet, regarding its pharmacological potential, mainly due to the absence of chemical analyses of the plant’s components. Therefore, it is emphasized the significance of phytochemistry in the search of knowledge and identification of active chemical compounds which may influence the pharmacological responses of plants with medicinal interest. Thus, the objective of this study was to identify the major compounds present in the essential oil of Hyptis martiusii Benth (OEHM). The oil extraction was made using 250g of fresh leaves and 1,5L of water, maintained on ebullition for two hours in a 5L round-bottom flask. The resulting mixture of water and oil was collected in a modified Clavenger apparatus, than it was separated and dried with anhydrous sodium sulfate (Na₂SO₄). The chemical analysis of OEHM was performed by gas chromatography coupled to mass spectrometry (GC/ME) and its compounds identification were performed by comparing the obtained mass spectrum with already existing patterns in literature. Twenty compounds were identified in OEHM, where mono and sesquiterpenes were the most representative (93,99% of the oil composition), among them, 1,8-cineol was characterized as the major compound. Analysing other studies, it was observed that many representatives of the genus Hyptis crenata have presented similarities, regarding chemical composition of the essential oils. For instance, Hyptis crenata Pohl has, among others, camphor, 1,8-cineole, α-pinene, β-caryophyllene, which have also been identified in OEHM. Thus, it is emphasized the importance of researching on its isolated compounds, in order to know its possible pharmacological properties.