The effect of the forming temperature and the magnetic field was investigated for the charge retention and stability of poly(methyl methacrylate) (PMMA)–magneto electret (ME) samples with thermally stimulated discharge currents (TSDCs) and a surface-charge-decay mechanism. The measurements were performed on a pristine PMMA sample with a thickness of 20 mm. The comparative studies of charge decay with TSDC indicated a strong resemblance between the results of the two techniques of MEs of PMMA and were characterized by two TSDC peaks, that is, an α peak at 110°C and a ρ peak at 160°C. The low-temperature peak (i.e., the α peak) was associated with dipolar relaxation, and the high-temperature peak (i.e., the ρ peak) was attributed to the self-motion of space charges in PMMA. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.