A silicone oil-based carbon paste electrode plated "in situ" with a bismuth film, BiF(C/SO), has been tested for differential pulse anodic stripping voltammetry of heavy metal ions in highly alkaline media. First, the BiF(C/SO) was examined with respect to its polarisability in solutions of either NaOH or KOH with varying concentration. Further, strpping characteristics of selected metals (Zn, Cd, Pb, and Tl) were investigated in order to define analytical performance of the BiF(C/SO) in 0.1 M KOH chosen as optimal medium. The study has revealed some specifics of measurements in solutions with high pH due to complex-forming capabilities of the OH- ions, contributing thus to the continuing characterisation of bismuth film-based electrodes.