Kingella (Moraxella) kingae occasionally colonizes the nasopharynx and rarely causes serious infections. Three children with K kingae infections treated over a two-month period were studied. Epidemiologic investigation concluded that infection was community acquired, not pseudoinfection or nosocomial infection. Except for prompt laboratory recognition of the organism, no identifiable factors explained the observed prevalence. Five additional K kingae infections were reviewed. Affected sites included blood (two), valves (two), bone (two), joint (one), and disk space (one). Three patients had underlying disease; one was immunosuppressed. Kingella kingae resembles other members of the Neisseriaceae family and causes similar infections except meningitis. It is differentiated by colonial characteristics and standard biochemical tests. Treated infections responded to penicillin G potassium. Gram-negative bacteria uncommonly are implicated in endocarditis, arthritis, osteomyelitis, and diskitis; K kingae deserves recognition as a pathogen in these pediatric infections.