Palavras-chave: Pterodon emarginatus, Plantas medicinais, Óleos essenciais.ABSTRACT: Evaluation of the antimicrobial activity of the essential oil of sucupira (Pterodon emarginatus). The use of plants for therapeutic purposes is one of the oldest forms of medical practice. This has aroused scientific interest through studies on the antimicrobial activity of extracts and essential oils from plants for the purpose of creating alternatives to combat microorganisms resistant to antibiotics. The objective of this study was to evaluate the potential antimicrobial activity of the essential oil of Pterodon emarginatus against Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922. The essential oil of P. emarginatus was extracted by the method of hydrodistillation by steam distillation using a modified Clevenger apparatus. Antimicrobial activity was determined using the method of diffusion in solid medium by the pour plate technique using pure essential oil (100%) at the following concentrations: 32%, 16%, 8%, 4%, 2%, 1% and 0.5%. None of the concentrations formed zones of inhibition for Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853 and Escherichia coli ATCC 25922. The present findings suggest that the essential oil of P. emarginatus has no antimicrobial activity against S. aureus. P. aeruginosa and E. coli.