The microorganisms isolated in 1981-1985 from 171 cases of septicemia in patients with hematological malignancies were on the whole the same as those found in 1970-1972. The distribution between species was also quite similar for the two periods except within staphylococci, where the isolation rate of coagulase-negative staphylococci was higher in the latter period while that of Staphylococcus aureus was lower. Of 67 strains of Enterobacteriaceae tested for an aminoglycoside, 6% were found to be resistant, whereas 8% of 48 Enterobacteriaceae strains were found to be cefotaxime resistant. Methicillin- or aminoglycoside resistant S. aureus did not occur.