A case of Pseudomonas sepsis and meningitis is described in a family in which the first child died in the first year of life after a fulminant Pseudomonas sepsis. In our patient, the second son, treatment was begun immediately after admission with clinical and bacteriological signs of Pseudomonas sepsis and continued for a 4-week period. Subsequent cessation of the treatment resulted in a relapse, with meningeal involvement. After specific therapy was added for his immunologic incompetence, as well as subsequent antibiotic treatment, the patient was cured of his prolonged illness.