Several clostridial genomes have been sequenced in the past few years, and new sequencing projects as well as postgenomics approaches to study this important anaerobic genus are under way. This wealth of sequence data extends our knowledge of the metabolic versatility of this genus and its potential biotechnological exploitation and also adds to our view of virulence traits of pathogenic clostridia. So far, little is known about the clostridial cell surface and its role in the interaction with the respective environment. This is of special interest in understanding the host interaction of intestinal clostridia, which are assumed to influence the integrity of the gastrointestinal tract. Here recently sequenced clostridial genomes are explored with respect to features of cell surface association. Several classes of proteins with cell wall-binding domains are found, including S-layer proteins and adhesins. It could be shown that most species are specifically equipped with surface-associated factors, resulting in distinctive host/matrix-interacting properties.