Twenty ruthenium (II) complexes (1-5) were evaluated for their in vitro antibacterial and antifungal activity against Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853), Candida albicans and Candida tropicalis. Compounds 1d, 1e, 1h, 1i and 1j showed more pronounced antimicrobial activity against Gram-positive bacteria and fungi as compared to the nitrogen donor ruthenium complexes; hydrophobic substituents were significantly more effective. None of the compounds 1-5 exhibited antimicrobial activity against the Gram-negative strains Escherichia coli (ATCC 25922) and Pseudomonas aeruginosa (ATCC 27853) with the concentrations ranging between 12.5 and 800 micrograms/ml.