Techniques to reliably quantify left ventricular myocardial mass (LVMM) are mandatory for monitoring therapy in patients with left ventricular hypertrophy (LVH). The purpose of this study was to measure LVMM and volumes by cine magnetic resonance imaging (MRI), and to assess acute changes through hemodialysis as a model for different loading states. Seven dialysis patients with LVH were examined before and immediately after hemodialysis. All MR imaging was done with a steady-state free precession (SSFP) cine sequence (TrueFISP; TR, 3.2ms; TE, 1.6ms; flip angle, 60°; slice thickness, 8 mm). LV volumes, ejection fraction (EF), and LVMM were determined by slice summation after manual planimetry in short axes. A significant reduction of end-diastolic volume (EDV) (mean pre, 140 mL; post, 109 mL; p < 0.01), end-systolic volume (ESV) (49mL → 42mL; p < 0.05), and stroke volume (91 mL → 66mL; p < 0.01) through dialysis was revealed by MRI. Ejection fraction did not change significantly. A slight decrease in LVMM was detected in all patients (mean pre, 184 g; post, 177 g; p < 0.05). Intra- and interobserver variability for EDV, ESV, and LVMM were 1.3 ± 6.2mL, -0.9 ± 4.1mL, -1.4 ± 3.9g, and 3.3 ± 7.5 mL, 2.6 ± 5.0mL, - 2.4 ± 4.6g, respectively. Standard error of estimation (SEE) was ±2.3mL, ±2.0mL, ±1.6g, and ±2.6mL, ±2.1mL, and ±2.0g for intra- and interobserver variability. In conclusion, cine MRI is a reliable technique for LVMM measurement that is independent of LV loading status. This method allows for detection of small changes, which is crucial for accurate therapy monitoring in LVH. Left ventricular myocardial mass and volumes decrease significantly during hemodialysis.