BACKGROUND: The treatment for Kawasaki disease (KD) patients refractory to intravenous immunoglobulin (IVIG) therapy is still controversial, and the efficacy of plasma exchange (PE) and infliximab (IFX) therapy for infantile KD is unknown. METHODS: A total of 22 infantile KD patients refractory to initial and additional IVIG, who received either PE or IFX as third-line therapy from October 2008 to February 2020 were examined retrospectively. The patients' sex, age, days of first IVIG, days of PE or IFX therapy, laboratory data preceding PE or IFX therapy, coronary artery lesions (CALs), and adverse effects were investigated. RESULTS: Thirteen patients received PE and nine patients received IFX as the third-line therapy. For the median age at onset, the median days of first IVIG and PE or IFX, and pre-PE or IFX therapy blood test results, there were no significant between-group differences. At admission, and before and after the third-line therapy, there were also no significant differences in occurrence of CALs. The frequency of serious adverse events was significantly higher in the PE group than in the IFX group. CONCLUSIONS: Although there were no significant differences in patient background, blood test results, or frequency of CALs, the frequency of adverse events was significantly higher in the PE group. With the trend of expansion of IFX therapy for KD patients refractory to IVIG, the role of PE as the additional therapy may become more limited.