The thermally stimulated depolarization current (TSDC) in the range of 250 to 400 K and d.c. conduction of poly (dimethyldiallylammonium chloride) (poly(DMDAAC)) were investigated in vacuum to obtain information about the type and the behavior of the polarization and the conduction processes, especially dependence on molecular mass and electrical field strength. The TSDC spectrum shows one peak with Arrhenius character up to 316 K but deviates from it at higher temperature. A maximum dielectric response was observed at a molecular mass of 110 000 g mol(-1). Activation energies of about 0.45 eV for polarization currents and 0.85 eV for conduction currents were obtained. The released charge Q depends on the voltage U following the power law, Q proportional to U-1.2. For the conduction current, I proportional to U-1.5 was obtained. The polarization was caused mainly by a dipolar process, with some contribution from charge carriers.