Objective To evaluate the etiology, treatment and outcome of neonatal arrhythmia. Methods The clinical data and short-term follow-up results of neonates diagnosed with arrhythmia from June 2017 to May 2020 were retrospectively analyzed. Results Twenty-three cases with neonatal arrhythmia (11 boys and 12 girls) were included. The mean gestational age was (36.2±2.9) weeks and the mean birth weight was (2784.8±727.7) grams. There were 12 full-term and 11 preterm infants. Abnormal fetal heart rhythm of 8 cases were observed in the prenatal period. There were 9 cases of ectopic beats, 12 cases of tachycardia and 2 cases of conduction block. The main causes of arrhythmia were cardiac structural abnormality, neonatal respiratory distress syndrome and asphyxia at birth. Fourteen cases did not have clear etiology or clinical symptoms. Twelve cases with tachycardia were treated with anti-arrhythmia drugs or electrical cardioversion, while those without clinical symptoms (6 cases of supraventricular premature beats, 3 cases of ventricular premature beats and 1 case of atrioventricular block) did not receive anti-arrhythmia therapy. Four neonates died (17.4%) eventually. Serum levels of creatine kinase, creatine kinase-MB isoenzyme, cardiac troponin T and B-type natriuretic peptide in death group were significantly higher than those in survival group, and the difference was statistically significant (P<0.05). Of the 19 infants who survived until discharge, 11 showed abnormal rhythm on dynamic electrocardiogram, and 2 were treated with oral anti-arrhythmia drug after discharge. By 1 year of age, none of the patients had been readmitted to the hospital for symptomatic arrhythmia. Conclusions Arrhythmia may occur in newborns with underlying diseases, or without clear cause or clinical symptoms. The prognosis of patients with elevated myocardial markers is poor. Rapid arrhythmia should be considered as soon as possible. For those without clear cause or symptoms, those with good heart function, no intervention should be involved, but need to be closely followed.