Mass transport in the hanging meniscus configuration has been studied. The effects of this geometry on an electrochemical reaction of a gas phase species with a high solubility in the electrolyte phase have been investigated, both numerically and experimentally. The steady-state process is modelled in cylindrical polar coordinates using a fully implicit finite-difference numerical method and solved with a preconditioned Krylov subspace method, The numerical method incorporates an expanding mesh technique to optimise electrode flux error-cancelling. The nature of the meniscus boundary such as to permit the ingress of electroactive material mentioned, but not the egress of electrode reaction products is shown to result in a diffusional overpotential in the steady-state voltammogram. This observation has been examined experimentally by using the reduction of O-2 in dimethylsulphoxide solution on a Au(lll) single crystal electrode.