From 1984 to 1986, 1038 Gram positive cocci (865 Staphylococci and 173 Enterococci) have been tested for sensitivity to teicoplanin by the agar diffusion method: only one strain (Staphylococcus haemolyticus) resulted to have no zone of inhibition around the teicoplanin disk. All Staphylococcus haemolyticus strains showed higher MIC: 2.79 mcg/ml after 24h of incubation and 20.50 mcg/ml after 48h. The reduced teicoplanin sensitivity of Staphylococcus haemolyticus was not detected by the agar diffusion test.