The impending EU-wide ban on the use of antibiotic growth promoters (AGP), and potential legislation over the use of zinc oxide (ZnO), necessitates the need to find credible alternatives. Zinc oxide has proven to be effective at promoting post-weaning growth and reducing the incidence of diarrhoea, although its mode of action remains unclear. The use of probiotics is often proposed as an alternative, but their efficacy remains unpredictable and unproven. Probiotics do, however, have the potential to modulate the gastrointestinal microbiota and immune response (Perdigon et al., 1995). This experiment aimed to investigate whether dietary supplementation with ZnO and a recognised and characterised probiotic strain would enhance post-weaning piglet performance in the absence of AGP.