Electrophysiological characterization is crucial for validating the function of human cardiomyocytes derived from pluripotent stem cells. To examine the maturity of human cardiomyocytes generated, whole-cell patch clamp recordings for action potentials and IK1 current are required. Here we report a summary of electrophysiological recording procedures using human mature cardiomyocytes isolated from engineered cardiac tissues derived from pluripotent stem cells. As observed in rodent primary myocytes, human mature engineered myocytes could be more difficult for whole-cell patch clamp recordings compared to conventional cardiomyocytes spontaneously contracting, which are differentiated from human pluripotent stem cells. Especially, we found that time window to record the electrical activities in such mature myocytes was narrower than ones in human conventional cardiomyocytes spontaneously beating. The whole workflow could be useful to facilitate electrophysiological characterization of human engineered cardiomyocytes in order to unveil the pathophysiological mechanisms underlying cardiac disease and test drug candidates.