Over the last twenty years there has been an alarming increase in isolation of Streptococcus pneumoniae strains with a reduced susceptibility not only to penicillin, but also to other betalactams and macrolides. This phenomenon justifies the great interest in new antibiotics. Cefditoren, a new aminothiazolyl oral cephalosporin, recently commercialized in Italy, is characterized by an extended activity against penicillin-resistant S. pneumoniae. The aim of this study is to evaluate the incidence of the resistance/susceptibility to various antibiotics in 1000 strains of S. pneumoniae (678 SPSS, 219 SPPI and 103 SPPR), clinically isolated during 2009. The data obtained by our in vitro study show that cefditoren is the most active agent against S. pneumoniae. In fact, the MIC90 values of 0.5 micrograms/ml obtained could be particularly significant in therms of therapeutic predictivity.