Our clinical experience with new antibiotics giving special consideration to the individual cephalosporin groups is discussed. Although newer cephalosporins from cefamandol and cefoxitin to cefotiam and cefoperazon already showed increased effectiveness (for example, cefoxitin in bacteroides infection) in comparison to older ones, the real breakthrough regarding enterobacteriaceae was only made with cephalosporins of the cefotaxime group. This group's main indication is non-specific initial therapy of severe nosocomial infections, especially processes in which the presence of resistant enterobacteriaceae must be assumed. Because of its broad spectrum of action, cefotaxime can to a large extent replace the combinations with aminoglycosides which were used previously. When required, cefotaxime proves to be a good partner for combinations with pseudomonas antibiotics.