Information on the constituent of medicinal plants used in Sudanese ethnomedicine is very scarce. This study was aimed to investigate the chemical constituents of the medicinally important Mentha viridis essential oil and to evaluate its antimicrobial activity. 52 components were detected by GC-MS Analysis. Major constituents are: D-carvone (39.87%) and D-limonene (22.36%). The antimicrobial activity of the oil was evaluated via disc diffusion method against five standard human pathogens (Gram positive: Staphylococcus aureus and Bacillus subtilis; Gram negative: Escherichia coli and Pseudomonasa aeruginosa and the fungal species Candida albicans). The oil showed significant activity against Pseudomonasa aeruginosa and Bacillus subtilis beside moderate activity against Staphylococcus aureus. However it was inactive against other test organisms.