Nano/micro-carrier systems have shown promising application in the biomedicalfield as various deliverycarriers. The composite material and fabrication method determine their microstructures, properties andthus their potential applications. Since approved as tablet coating material by the U.S. Food and DrugAdministration (US-FDA), zein has been widely investigated as one of protein-based materials in the pastfew decades. Zein is renewable, biodegradable and relatively inexpensive in comparison with animalproteins (e.g., gelatin and albumin). This paper reviews the current landscape of zein-based nano/micro-carrier systems, with particular emphasis on nano/microparticles, nano/microcapsules and their design,fabrication, assembly mechanisms and biomedical applications especially for controlled drug delivery.The benefits, challenges and related solutions of zein-based colloidal carrier systems are also discussed.In addition, investigations on the molecular structure, biocompatibility and immunogenicity of zein aresummarized and discussed.