The effects of septic insult were compared in a canine model of splenic reimplantation. Sequential changes in hematologic, hepatic, and immunologic function were monitored biweekly in 18 dogs during 10 months after splenectomy, splenectomy with reimplantation, or sham operation. There was no significant difference in these measures between the two groups. At the end of the 10-month period, spleen scans with technetium (99Tc) labeled, heat-damaged RBCs were obtained on the reimplanted dogs. 99Tc scanning revealed no active splenic implants at 10 months. All dogs were then infected with intravenous Type III pneumococcus for 9 consecutive days. There were no measurable hematologic, hepatic, or immunologic differences between groups before or after the septic insult. These animals were then sacrificed for histologic analysis of the splenic reimplants. Reimplant histology showed active germinal centers, but the surrounding pulp was fibrotic and lymphocyte-depleted. Splenic reimplantation in this canine model yields no apparent benefit.