Abstract Fast cyclic voltammetry at carbon fibre microelectrodes was used to monitor stimulated release of electroactive species simultaneously in both caudate and nucleus accumbens. The released species was identified as dopamine in both nuclei on the basis of anatomical, electrochemical and pharmacological criteria. Dopamine release in the nucleus accumbens was consistently evoked at more ventromedial stimulation sites than for caudate. In both nuclei, release was reduced or abolished by α-methyl- p-tyrosine and Ro 41284. Pargyline, cocaine and GBR 12909 potentiated release while desipramine had no effect. In conjunction with the electrochemical data, the results indicate that dopamine is the sole species detected in caudate and accumbens following stimulation of the median forebrain bundle.