A melt-processable polyaniline complex was blended with polypropylene under different mixing conditions and melt-spun into fiber filaments under different draw ratios. The conductivity, electrical resistance at different voltages, and morphological characteristics of the prepared fibers were investigated. The morphology of this two-phase blend was demonstrated to have a large effect on the conductivity level and the linearity of the resistance-voltage relationship of the blend fibers. Two factors had substantial effects on the morphology and electrical properties of the fibers. They were the size of the initial dispersed conductive phase, which depended on the melt blending conditions, and the stress applied to orient this phase to a fibril-like morphology, which was controlled by the draw ratio of the fiber. The two factors were shown to be associated with each other to maintain an appropriate balance of fibril formation and breakage and to create continuous conductive pathways. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 119: 558-564, 2011