Abstract Background Inferolateral T wave inversion has been associated with increased risk of mortality and sudden cardiac death (SCD) in general population. However, the association between isolated T inversion and SCD is still unclear. Purpose The purpose of this study was to examine whether isolated T inversion associates with SCD, and find out possible gender differences. Methods FinGesture Study has systematically collected clinical data and medico-legal autopsy data from 5,869 consecutive SCD victims (mean age 64.9±12.4 yrs.) in Northern of Finland between years 1998 and 2017. Previously recorded electrocardiograms (ECG) were available and analyzed in 1,101 subjects. The control group consisted of 7,217 subjects representative of Finnish general population (mean age 51.5±12.4 yrs.). T inversion was interpreted isolated if there was at least two T inversions ≥−0.1 mV in at least two contiguous leads, and there were no ECG signs of left ventricular hypertrophy (LVH) defined by Sokolow-Lyon criteria or bunchle brand block (BBB) attached to it. Results In a current study, isolated T inversion was more common finding among SCD victims compared to general population: isolated T inversion in any leads 10.9% vs. 0.9% (SCD vs. general population, p<0.001), laterally 7.7% vs. 0.1% (p<0.001), inferiorly 3.2% vs. 0.5% (p<0.001) and anteriorly 2.9% vs. 0.4% (p<0.001). Particularly, isolated T inversion seemed to assoaciate with ischemic SCD taking into account that 61.5% of the total isolated T inversions were seen in ischemic SCD victims (p=0.018). In addition, 62.1% of the inferior isolated T inversions (p=0.023) and 61.7% of the lateral isolated T inversions (p=0.031) were in ischemic SCD victims versus 37.9% and 38.3% in non-ischemic SCD victims, respectively. The prevalence of isolated T inversion in any lead was also higher among male SCD victims compared to female victims (12.8% vs. 8.2%, p<0.001, respectively). There was no statistically significant difference in the prevalence of LVH and strain changes between the populations. Among bundle branch blocks left BBB was predictably more typical in SCD victims (5.8% vs. 0.5%, p<0.001). Conclusion We noticed an association between isolated T inversion and SCD. The association was most prominent in males and in those with ischemic etiology of SCD. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): The Finnish Medical Foundation, Finnish Foundation for Cardiovascular Research