Two outbreaks of Pseudomonas infections involved 14 patients in a pediatric intensive care unit during a six-month period. Organisms of the same pyocine type were isolated from three of four patients infected during the second outbreak. Introduction of Pseudomonas aeruginosa to the unit was suspected to have occurred by patients transferred from outlying hospitals. Epidemiologic studies failed to reveal a contaminated fomes, and hospital personnel likely served as intermediaries to spread the organism within the unit. Statistically, newborn infants wre much more likely to become infected and to die from Pseudomonas infections than older patients. This report stresses the epidemic potential inherent in pediatric intensive care units, particularly those dealing with neonates. A suggested scheme for surveillance is presented.