Various electrical properties such as electrical conductivity, electrostatic charge and its half-life time, and electromagnetic shielding effetiveness were studied for antistatic polyester film and fabric prepared by exposing modified poly(ethylene terephtalate) (M-PET) containing ferric chloride as an oxidant to pyrrole vapor. Higher content of FeCl3 led to higher eletrical conductivity, however shorter time to the saturation conductivity. It was found that just above the critical polypyrrole(PPy) content, 1.5wt %, electrical conductivity increased rapidly to the saturation value, 1O-$^3$ S/cm. Morphological feature of the antistatic film, i.e. homogeneous and dense distribution of PPy on the film surface, was found to be another preferential factor improving the electrical conductivity. The initial electrical conductivity of antistatic film was retained even after 30 days at room temperature under atmospheric environment. As compared with the M-PET fabric itself, the antistatic fabric was found to have lower maximum electrostatic charge by about three orders and shorter half-life time by about two orders. Also the antistatic fabirc exhibited good electromagnetic shielding effectiveness which read 24 dE at 300 MHz.