The ac conductivity of semiconducting trans-polyacetylene has been measured over the frequency range 10 Hz to 10 MHz at room temperature. Both ohmic and blocking contacts were used on samples prepared at several doping levels below the metallic limit. The complex conductivity was found to be frequency independent for all levels of doping and for both types of contacts. A discussion is given regarding soliton motion and inhomogeneous doping and their possible effects on ac conductivity in trans-polyacetylene. © 1980, All rights reserved.