The reaction of K(2)PtCl(4) with anticancer-alkylating agent mechlorethamine hydrochloride (CH(3)NH(C(2)H(4)Cl)(2) x HCl = HN2×HCl), in the molar ratio 1 : 2, affords the complex [H2N2](2)[PtCl(4)]. In vitro antimicrobial and lipoxygenase inhibitory activities of the complex and its precursor were evaluated. Antimicrobial activity of the HN2×HCl and [H2N2](2)[PtCl(4)] complex was investigated against 29 species of microorganisms. Testing is performed by microdilution method. Minimum inhibitory concentration (MIC) and minimum microbicidal concentration (MMC) have been determined. The difference between antimicrobial activity of precursor and corresponding platinum(II) complex is noticed and the activity of the precursor was higher. Tested compounds demonstrated the high and significant antifungal activity and low to moderate antibacterial activity. It was shown that the gram-positive bacteria were more sensitive than the gram-negative. UV absorbance-based enzyme assays were performed with HN2×HCl and [H2N2](2)[PtCl(4)] complex, in order to evaluate their in vitro inhibitory activity of soybean lipoxygenase (LOX), also. Assay with LOX showed significantly greater inhibitory activity of the complex, than the precursor.