PURPOSE: Heart weight is a key parameter for assessing cardiac pathology, typically determined postmortem during autopsies. In forensic practice, the evaluation of cardiological records is crucial, particularly in sudden cardiac death cases, to identify pre-existing cardiac pathology. The comparison of ante- and postmortem cardiac pathology is challenging given the differing conditions of cardiological and forensic examinations. This study aimed to evaluate whether the echocardiographically combined calculation of left ventricular mass (LVM) and right ventricular mass (RVM) can nearly approximate the ‘true’ (postmortem) heart weight. METHODS: The hearts of 60 deceased were weighed after dissection, removal of blood and blood clots, rinsing, and drying. Antemortem echocardiographic measurements of the same individuals were used to calculate RVM and LVM. The sum of LVM and RVM was compared with postmortem heart weight, whereby epicardial fat and atrial tissue were included in the postmortem heart weight. RESULTS: Results showed relevant differences between estimated ventricular heart mass and postmortem heart mass (198.0–248.7 grams), with a strong Pearson correlation and a poor intraclass coefficient. The postmortem interval showed no relevant influence on the differences. CONCLUSION: Possible explanations for these differences include postmortem changes, geometric alterations due to cardiac disease, measurement inaccuracies, and the exclusion of atrial tissue and epicardial fat. In conclusion, echocardiography provides a useful antemortem approximation of ventricular heart mass with implications for both clinical and forensic practices, but the estimated ventricular heart mass should be interpreted with caution and should not be used as a substitute for the total heart weight.