Abstract: Controlled interfacial accumulation of diltiazem(I) on a hanging-mercury-drop electrode was the basis for a sensitive adsorptive stripping-voltammetric procedure. The effects of various operational parameters on the stripping response are discussed. With pre-concentration for 3 min at a potential of -0.9 V (termination of scan at -1.9 V), an 11-fold enhancement of peak current was observed, which resulted in a detection limit of 4 nM-I. The anodic response of I at carbon electrodes was also used for amperometric detection in flow injection analysis; measurements gave a detection limit of 1 to 5 ng of I.