Background: There is limited information available regarding the role of infliximab (IFX) following the acute phase of Kawasaki disease (KD). We aimed to evaluate whether IFX is associated with coronary artery aneurysm (CAA) regression. Methods: Between 2005 and 2016, we identified 971 consecutive patients with KD from 3 tertiary institutions, and 49 (5%) with CAAs were enrolled in our study. Patients were divided into 2 groups: 27 who received IFX and 22 who did not. The persistence rate of CAAs was compared between the groups. Results: Age, sex, and duration of the febrile period did not significantly differ between the groups. The maximum value of C-reactive protein was higher in the IFX- than in the non-IFX group. The maximum z-score of CAAs did not differ between the groups. The 2-, 4- and 6-year cumulative persistence rate of CAA was 24%, 24% and 24% in IFX-group, whereas 67%, 52% and 33% in non-IFX group, respectively (P = 0.03). The median duration of CAA regression was 1.1 vs. 4.6 years. Among those who developed medium- or large-sized CAAs, the 2-, 4- and 6-year cumulative persistence rate of CAA was 33%, 33% and 33% in IFX group, whereas 77%, 51% and 48% in non-IFX group, respectively (P = 0.047). Multivariate logistic regression analysis indicated that the maximum z-score (hazard ratio 0.72, p < 0.001) and response to IFX (hazard ratio 4.56, p = 0.017) were independently related to regression. Conclusion: IFX therapy was observed to be effective for the early improvement of CAAs in patients with intravenous immunoglobulin-resistant KD.