A series of 1-ethyl-6,8-difluoro-4-oxo-7(4-aryl piperazin-1-yl) 1,4-dihydro-quinoline-3-carboxylic acid derivatives (6a-f) and 1-ethyl-6,8-difluoro-4-oxo-7(4-piperidin-1-yl) 1,4-dihydro-quinoline-3-carboxylic acid derivatives (7a-e) were synthesized and evaluated for antibacterial and antifungal activities. The antimicrobial activities of the compounds were assessed by the microbroth dilution technique. The compounds were also evaluated for antifungal activity against Candida albicans (ATCC 90028) and Cryptococcous neoformans (ATCC 14116) pathogens. The preliminary in vitro evaluation studies revealed that some of the compounds have promising antimicrobial activities.