Coronary artery complications are the most severe complications in Kawasaki disease (KD). Its cause is unclear but superantigens are considered to influence KD. This study aimed to determine whether coronary artery complications and level of Nterminal pro-brain natriuretic peptide (NT-proBNP) are associated with Mycoplasma pneumoniae (MP) in patients with KD. We studied 142 pediatric patients diagnosed with KD. MP immunoglobulin M (IgM) antibody examination was conducted. All patients underwent echocardiography, and coronary artery dilatation was defined as a coronary Z-score >2.0. We also evaluated their NT-proBNP findings. The independent t-test and Pearson chi-squared test were used to analyze betweengroup differences; a p-value <0.05 was considered statistically significant. Forty children were MP IgM positive. MP IgMpositive patients were older than MP IgM-negative patients. There was no significant difference in the clinical manifestations between the groups. Comparison of the mean Z-score of the coronary artery revealed that only the Z-score of the left anterior descending artery was significantly different between the groups. However, the number of patients with coronary artery dilatation was not significantly different between the groups. Our findings demonstrated no relationship between MP infection and coronary artery dilatation or NT-proBNP levels in patients with KD.