Adsorptive stripping voltammetry was used for the determination of trace amounts of the benzodiazepines camazepam and bromazepam. This very sensitive method is based on controlled adsorptive pre-concentration of the drugs on the hanging mercury drop electrode. Measurements were taken by differential-pulse voltammetry after determination of the optimum accumulation conditions. The response was linear in the range 3 × 10^–9–9 × 10^–9M(270 s and-0.60 V for the pre-concentration) for camazepam and 1 × 10^-8–8 × 10^–8M(90 s and-0.40 V) for bromazepam. In the concentration ranges investigated, the relative standard deviation was lower than 6%. The method is applicable to the determination of the drugs in human serum, with detection limits of 20 ng ml^-1 of serum (30 s and-0.62 V for the pre-concentration) for camazepam and 200 ng ml^–1 of serum (10 s and-0.41 V) for bromazepam.