The effects of dopant 5-sulfosalicylic acid on the conductivity of polypyrrole were investigated. Being nonhygroscopic, ammonium persulfate was used as the oxidant. Under the condition of fixed molar ratio of oxidant-to-monomer (0.375:1.00), a dozen of polypyrrole samples were made from chemical polymerizing the monomer pyrrole in aqueous medium by varying the dopant-to-monomer molar ratio. It was found that the dopant affected the conductivity and particle size of the synthesized polypyrrole. A maximum value for electrical conductivity of 5575 S/m was achieved when the molar ratio of dopant: oxidant: monomer is 2.25:0.375:1.00.