Introduction Supraventricular tachycardia (SVT) is the most common arrhythmia in the neonatal period, but its association with other triggering processes is not well established. The aim of the study was to analyse the possible relationship between neonatal SVT and gastroesophageal reflux disease (GERD), a condition which was recently linked to atrial arrhythmias. Material and methods A retrospective longitudinal descriptive study was conducted over a period of 5years on newborns who were diagnosed with SVT in a level III neonatal unit, assessing morphological aspects, associated symptoms, and treatments received. Its association with GERD and the impact of this on SVT was studied. Results Eighteen patients (1.2 per 1000 newborns) were diagnosed with SVT. Fifty percent of them were combined with clinically significant GERD (P=.01), and all of them received drug treatment. The average time of control of SVT without GERD since diagnosis was 6 days (95% CI: 2.16-9.84, with a median of 3) and 7.6 days when both pathologies were present (95% CI: 4.14-10.9, with a median of 7) (P=.024). Conclusions Patients with SVT in the neonatal period frequently have GERD, and this combination leads to more difficulty in controlling the tachycardia. The reflux could act as a trigger or perpetuator of arrhythmia, therefore it is important to find and treat GERD in infants with SVT.