 Probiotic encapsulation technology, PET, has the potential to protect microorganisms and to deliver them into the gut. Because of the promising preclinical and clinical results, probiotics have been incorporated into a range of products. However, there are still many challenges to overcome with respect to the micro-encapsulation process and the conditions prevailing in the gut. This paper reviews the methodological approach of probiotics encapsulation including biomaterial selection, choice of appropriate technology, in vitro-release studies of encapsulated probiotics and highlights the challenges to be overcome in this area. This article was authored by Gildus K. Bassi and Thierry Van Damme.