The essential oil and its separate fractions were isolated from the lemon balm leaves collected before the plant budding using the method of exhaustive hydrosteam distillation. The component composition of the oil and fractions was determined using the method of chromatography-mass spectrometry. The essential oil mainly contains sesquiterpene compounds and does not contain such monoterpenoids as citral, citronellal, geraniol. The antiradical activity of the oil and fractions was assessed during the reaction with a stable free 2,2-diphenyl-1-picrylhydrazyl radical. The values of the antiradical activity of the whole oil and its separate fractions correlate with the content of oxygen-containing terpenoids. The correlation coefficient is 0.81. The antimicrobial activity was studied using the disk diffusion method against strains of Staphylococcus aureus (MSSA), Staphylococcus aureus (MRSA), Escherichia coli, Pseudomonas aeruginosa and Candida albicans. Whole essential oil of lemon balm leaves and its separate fractions completely inhibit the growth of Staphylococcus aureus (MSSA). Fraction 1, collected during the first hour, showed fungicidal activity against Candida albicans, completely inhibiting the growth of the strain, both undiluted and diluted in a 1 : 1 ratio with 96% ethyl alcohol. Essential oil of lemon balm leaves collected before the plant budding is promising for further studies of its biological activity.