Micron/submicron-sized plastic debris in the environment is a global issue of increasing concern and may harm human health. A large number of studies have shown that plastic debris has various toxicological effects on different organisms. Thus, efforts have increased to replace conventional plastics with bioplastics. However, investigations on the relation of submicron-sized bioplastics- and conventional plastics to culture-dependent biofilm formation and their similarities and discrepancies are still very limited. For this purpose, two end products made from bioplastics and their equivalent end products from conventional plastics were used to examine the response of the biofilm formation of selected clinically important bacteria. To evaluate the similarities and differences of submicron-sized bioplastics and conventional plastics on biofilm formation, the physicochemistry (particle size, zeta potential, chemical composition, and surface chemistry) of the tested plastics was examined, as well as the characteristics of the biofilms (categorization, protein/carbohydrate).