Biological activities of Sorbus aucuparia L. leaves extract were tested in our study. This study aimed to investigate the activity of Cydonia oblonga Mill. peels and leaf ethanolic extracts on biofilm formation of different microbial strains, including pathogenic bacteria and food poisoning strains. It was shown that both of the investigated extracts inhibited biofilm formation in a dose dependent manner with sub-minimal inhibitory concentrations. The percentage of biofilm formation inhibition varied for each bacterial strain and was in the range of 10-100%, for both of the tested extracts. The ability of extracts to inhibit already formed biofilms presented as minimal concentration necessary to disrupt biofilms and concentrations was in the range of 10-100 µg/mL for the leaf extract and 5-75 µg/mL for the peel extract. The investigated extracts showed a promising antimicrobial effect comparable to, or even higher than the used reference compounds, which make these plant parts attractive for pharmaceutical and food industry.