Bacterial spores are robust and dormant life forms with formidable resistance properties, in part, attributable to the multiple layers of protein that encase the spore in a protective and flexible shield. The coat has a number of features pertinent to the emerging field of nanobiotechnology including self-assembling protomers and the capacity for engineering and delivery of foreign molecules. This review gives an account of recent progress describing the use of the spore, and specifically, the spore coat as a vehicle for heterologous antigen presentation and protective immunization (vaccination). As interest in the spore coat increases it seems likely that they will be exploited further for drug and enzyme delivery as well as a source of novel self-assembling proteins.