In the course of this work a rotating disc electrode has been employed to study the electropolymerisation of polypyrrole paratoluene sulfonate under hydrodynamic conditions. The effect of several solution additives with distinct properties such as a stabiliser (polyvinyl pyrrolidone), a catalyst (Tiron) and a surfactant (dodecylsulfate) has been considered. The effect of the rotation rate of the electrode on the initial polymer deposition potential and the polymerisation current was investigated. Experiments showed that polypyrrole was readily deposited onto the rotating electrode. Without the presence of the additives, the potential required to initiate polymer deposition increased positively with an increased rotation rate and a decreased polymerisation current. However, in the presence of the additives, the polymerisation/deposition behaviour varied markedly depending on the nature of the additive and the concentrations employed. �� 1994.