A series of Mannich bases of 2-alkyl-3-hydroxy-pyridine-4-ones, namely 2-alkyl-3-hydroxy-5-N-piperidylmethyl or N,N-dialkylaminomethyl pyridine-4-ones 9, 10 and 15-18, two derivatives of N-aryl-2-methyl-3-hydroxy-pyridine-4-ones 19, 20 and two N-alkyl derivatives of maltol, 21 and 22 were prepared. They were screened for their antibacterial and antifungal activities against a variety of microorganisms using micro plate Alamar Blue((R)) assay (MABA) method. Multiple linear regressions (MLR) analysis was performed for the synthesized compounds as well as a series of pyridinone and pyranone derivatives 23-43 which have been synthesized and evaluated for antimicrobial activity by other researchers previously. Studied compounds showed a better quantitative structure-activity relationship (QSAR) model for the antimicrobial activity against Candida albicans and Staphylococcus aureus in comparison with other tested microorganisms.