The methanol extract of the aerial parts of Artemisia herba alba belonging to the family Asteraceae were screened for their antimicrobial activity against four standard bacteria: two Gram positive (Bacillus subtilis, Staphylococcus aureus), two Gram negative (Escherichia coli, and Pseudomonas aeruginosa) and two fungi (Aspergillus niger and Candida albicans) using the Disc diffusion method. The methanol extracts of two parts showed high activity against the bacteria and fungi tested. The minimum inhibitory concentrations of the methanol extracts of aerial parts were determine against standard bacteria and fungi using the agar plate dilution method. The minimum bactericidal concentrations and minimum fungicidal concentrations were determined using the macro- broth dilution method. The antibacterial activity of five reference drugs and the antifungal activity of two reference drugs were determined against four bacteria and two fungi and their activities were compared with the activity of the plant extracts. The extracts was also evaluated for its cytotoxic activity using Brine shrimp lethality bioassay method.