Globally, the public health domain is increasingly emphasizing the need for surfaces that can resist bacterial contamination, as the consumption of bacteria-infected substance may cause illnesses. Thus, this study aimed to modify polyurethane (PU) synthetic leather surfaces by coating their upper layer with fluorine-functionalized nano-silica particles (FNPs). This simple modification imparted omniphobic characteristics, realizing anti-biofouling and self-cleaning properties. The effectiveness in preventing bacterial adhesion was confirmed by the dip-inoculation method using Escherichia coli O157:H7 and Staphylococcus epidermidis. Bacterial adhesion was evaluated based on bacterial counts using the pour plate method and by directly enumerating from scanning electron microscopy images. The attachment of bacteria to the modified omniphobic FNPs-coated PU leather surface decreased by over 98.2% compared to that on the bare surface. We expect that the method developed in this study will significantly reduce or even eliminate the potential risks associated with various biological cross-contamination scenarios, thereby enhancing hygiene standards.