Abstract : This study evaluated the effects of supplementing probiotic cell walls (PCW) containing Lactobacillus rhamnosus and Saccharomyces cerevisiae on growth performance, feed conversion, and immune responses of finishing pigs against Foot-and-Mouth Disease (FMD), Porcine Reproductive and Respiratory Syndrome (PRRS), and Classical Swine Fever (CSF) viruses. The experiment was conducted on 360 F1 crossbred pigs (Du × YL), divided into three treatments (three replicates of 30 pigs each): Control (C, no supplementation), FS (0.05% PCW in feed), and WS (0.05% PCW in drinking water). Results showed that PCW improved growth performance, nutrient absorption, and feed conversion efficiency, with an increase in weight gain of 3.23–4.52% and a reduction in feed intake of 2.09–4.72% compared to the control. PCW supplementation also enhanced antibody levels against FMD, PRRS, and CSF viruses, with statistically significant increases observed for FMD and PRRS, while the response to CSF was less pronounced and requires further investigation. Overall, PCW shows potential as an antibiotic alternative, contributing to improved economic efficiency, sustainability, and biosecurity in swine production.