Currently, in order to predict the drug-induced lethal arrhythmias torsade de pointes (TdP), in vitro hERG assay and in vivo ECG examination have been conducted. However, some drugs, that inhibit hERG or induce QT prolongation, don’t induce TdP. Therefore, more accurate evaluation method is desired. The method using human iPS cell-derived cardiomyocyte (hiPS-CM) can evaluate multiple cardiac ion channels including Na+, Ca2+ and K+ channels beyond a wall of the differentia of the animal species, so it is useful to predict TdP risk in a man. Japan iPS Cardiac Safety Assessment (JiCSA) verified the evaluation system using hiPS-CM and multielectrode array (MEA), and we have developed the method of TdP risk classification.MEA not only can measure field potential duration (FPD) corresponding to the QT interval, but also can detect arrhythmias like waveform such as early after depolarization (EAD) considered a cause of TdP. After the establishment of the MEA method using hiPS-CM, we evaluated a variety of 60 drugs. Further, we measured the protein unbound drug concentration, because the MEA was measured under conditions comprising protein. By comparing the concentration of the event occurrences (10% FPD prolongation and EAD onset, etc.) in the MEA and clinical blood concentration, we scored and classified TdP risk of drug to high, medium and low. Comparing the result of classification and clinical TdP occurrence, generally good results were obtained. Our method is able to predict TdP risk with high accuracy, and considered to be useful for the evaluation of new drug candidates.