We studied the sensibility of positive and negative Staphylococcus coagulase to ampicillin, dicloxacillin, feneticillin, hetacillin. A comparative study of the different degress of sensibility of positive and negative coagulase Staphylococcus was done too. As it is shown in table I and II, there is a significative difference of sensibility to some antibiotics. Table IIIalthough doesn't allow us to conclude with security if the positive coagulase Staphylococcus are more sensitive among, itselves, the negative ones or not, to the tested antibiotics.