The Etest was used for determining in vitro susceptibilities of 144 unique clinical isolates of penicillin-intermediate and resistant Streptococcus pneumoniae to cefepime, cefotaxime, and ceftriaxone. MIC ranges were 0.12-8 mug/ml for cefepime and 0.06-16 mug/ml for cefotaxime and ceftriaxone. MICs for 50% of the isolates for the three agents were equivalent at 1 mug/ml, whereas MICs for 90% of the isolates were 2 mug/ml for cefotaxime and ceftriaxone, versus 4 mug/ml for cefepime. The Etest is a practical means for determining susceptibilities of S. pneumoniae to cefepime and other cephalosporins in diagnostic laboratories.