The yearly changes of relative frequency of glucose-nonfermentative Gram-negative bacilli except for P. aeruginosa isolated from various clinical specimens over the past 5 years were studied. Acinetobacter anitratum was the most commonly encountered strain and P. maltophilia and P. putida were also frequently encountered during 1974 through 1977. In 1978, P. cepacia became a significantly predominant strain, which was 44.6% of all nonfermentative Gram-negative bacilli excluding P. aeruginosa isolated in Juntendo Hospital. Antimicrobial susceptibility patterns of 59 similar to 61 clinical isolates of P. cepacia in 1978 were studied by agar dilution method, standardized by the Japan Society of Chemotherapy. Miloxacin and minocycline inhibited more than 95% of the strain by the concentration of 6.25 micrograms/ml. Nalidixic acid and sulfamethoxazole were sensitive to approximately 52% and 75% of the strains respectively. The minimal inhibitory concentration of gentamicin, tobramycin, amikacin, kanamycin, apalcillin, piperacillin and pipemidic acid for most strains was more than 1.25 micrograms/ml. More than 90% of the strains were highly resistant to ampicillin, carbenicillin, sulbenicillin, ticarcillin, cefazolin, cefotiam, tetracycline, clindamycin and colistin.