Splenectomy is a recognized factor predisposing to the late complication of serious sepsis. The meningococcus has been listed as an important organism in postsplenectomy infection. A survey of the literature, however, revealed a total of only 13 documented case reports over a 31-year period, including ten pediatric cases. No documented cases of meningococcal sepsis in children following splenectomy for trauma were found. In an experimental mouse meningococcal infection model, the intraperitoneal LD50 was similar between normal and splenectomized mice (4 X 10(8) v 4 X 10(7) cfu, respectively; P = not significant). Bacteremic patterns were similar in both groups. Uniform survival was seen in normal and splenectomized mice after various intravenous challenge doses of meningococci up to 10(6) cfu. This was associated with efficient bacterial clearance in both groups. It appears unlikely that the defect resulting from splenectomy alone is an important predisposing factor in meningococcal sepsis.