Poly(tetrabromo-p-phenylenediselenide) (PBrPDSe) has been doped by IBr, H2SO3 and CH3COOH acids. The samples have been studied by X-ray photoelectron spectroscopy (XPS) and electron spin resonance (ESR). Conductivity measurements have also been performed on pressed pellet samples. It has been shown by XPS and ESR that, after doping, positive charges are localized on Se atoms. The conductivity of the acid-doped PBrPDSe exhibits an increase by about four orders of magnitude. However, the limit of 10(-7) Ohm (-1) cm(-1) appears difficult to overcome. This saturation effect could be attributed not only to charge localization on Se atoms but also to steric hindrance related to the substituent introduced on the backbone of the polymer.