With the predictability of oil shortage, there is a strong demand for renewable and sustainable raw materials. In this scenario, lignocellulosic material stands out as a potential solution. With the use of bio-refinery, they can be processed into high value added products through chemical, biochemical and thermochemical processes. A great source of lignocellulosic biomass today is the wood of Eucalyptus, which has high levels of production and productivity in Brazil, reaching numbers between 60-80 m3ha1year-1. In order to achieve a more efficient utilization of biomass in a biorefinery concept, it is necessary first to perform chemical analyses to define the operating conditions of the conversion processes, since heterogeneity and high chemical complexity is an inherent property of the biomass. In this context, this study aimed to chemically characterize and investigate the potential of three species of Eucalyptus (E. urophylla, E. saligna and E. dunnii) grown in Rio Grande do Sul state for biorefinery purposes. Results of higher heating value for E. urophylla, E. saligna and E.dunnii were similar (19.10, 19.10 and 19.15 MJ/kg respectively). However, cellulose content results for E. saligna (47.5%±2.40) were highlighted, being slightly higher thanthose for E. urophylla (42.75%±1.34) and E. dunnii (43.10%±1.13). Hemicelluloses content for E. urophylla (23.25%±0.78) was slightly superior to the others (20.35%±2.05 for E. saligna and 18.80%±2.40 for E. dunnii). Finally, it was concluded that the analysed species of Eucalyptus have high potential for biorefinery in thermochemical processes. The species E. urophylla has the greatest potential for biorefinery processes using hemicelluloses, and the species E. saligna has greater potential for biorefinery processes utilizing cellulose.