Plasma exchange is a therapeutic option in refractory Kawasaki disease (KD). However, the effects of other immunosuppressive treatments on plasma exchange therapy have not been studied. We investigated the effect of infliximab on plasma exchange in KD as well as on the outcome in patients with KD. We studied 16 patients with intravenous immunoglobulin-resistant KD who finally underwent plasma exchange. The patients were divided into two groups: patients who received infliximab before plasma exchange (infliximab group) and patients who did not (non-infliximab group). The infliximab group showed a lesser median number of required total plasma exchange sessions (P = .002) and higher change and reduction rates in C-reactive protein before and after the first plasma exchange (both P = .027) than that of the non-infliximab group. Infliximab administered before plasma exchange reduced the number of total plasma exchange sessions and improved the plasma exchange efficacy.