The conductivity and electron spin resonance (ESR) of polyaniline (PANI) - poly-methylmethacrylate (PMMA) nanoscale blends have been. studied. It has been found that the dependence of the specific volume conductivity on the PAN] content in PANT-PMMA blends can be described by a percolation. model with. extremely loin percolation "threshold" in the range 0.8 - 2% (vol.). The temperature dependence of ESR for the higher percolation threshold of a PANI PMMA blend has been studied in the temperature range 4.2-300K. It has been shown that a g-value for unblended PANI and the PANI-PMMA composites is close to the free spin value and is constant at all temperatures, while the spin population is temperature-depended. Based on. the temperature dependence of ESR, the existence of two types of spins (localized and delocalized) in the polymer blend is suggested.