Prior to the 1957-1958 epidemic of Asian influenza A, public health authorities in the United States warned that a high incidence of postinfluenzal staphylococcal pneumonia could be anticipated, and they widely publicized recommendations for limiting the severity of this complication.1,2In virtually all sections of the nation many cases of staphylococcal pneumonia did indeed occur; available data indicate that despite the forewarning the Staphylococcus accounted for the largest single group of fatalities due to postinfluenzal bacterial pneumonia.3 The purpose of the present report is to present and compare the findings, clinical course, and management in 11 fatal cases and 9 nonfatal cases of post-Asian-influenzal staphylococcal pneumonia occurring in Boston and environs; to analyze the properties of the strains of staphylococci responsible, and to demonstrate the importance of the rapid choice of effective antistaphylococcal chemotherapeutic agents. Materials and Methods Human Cases. —All the cases studied occurred in the months