Introduction: Cardiac magnetic resonance (CMR) is the gold standard for evaluating myocardial fibrosis. Few studies have explored the association between ventricular arrhythmias (VAs) and fibrosis in apparently normal hearts. We aimed to investigate the association between the occurrence and morphology of VAs and left ventricular late gadolinium enhancement (LV-LGE) in patients without known structural heart diseases. Methods: This study enrolled 78 patients with apparently normal hearts who underwent simultaneous 24-h ambulatory Holter electrocardiogram (ECG) and CMR examinations. The presence and extent of LGE was determined using CMR imaging and compared based on occurrence and morphology of VAs. The clinical characteristics were also recorded and calculated. Results: LV-LGE was observed in 19 (37.3%) and 4 (14.8%) patients with and without VAs, respectively (P=0.039). It was more frequently observed in patients with polymorphic VAs (P=0.024) and ST-segment depression (P=0.001), and its extent was greater in polymorphic VAs than monomorphic VAs, with a difference that approached significance (P=0.055). In multivariate analyses adjusted for other clinical variables, the presence of ST-segment depression (HR: 8.83; 95% CI: 2.23-35.50; P=0.002), drinking (HR: 6.84; 95% CI: 1.63-28.56; P=0.008), and polymorphic VAs (HR: 25.24; 95% CI: 3.88-164.06; P=0.001) were associated with greater prevalence of LV-LGE. Conclusion: In this cohort of patients without structural heart diseases, myocardial fibrosis was associated with multiple VA morphologies and ST-segment depression on Holter ambulatory ECG measurements.