Simultaneous adsorptive stripping voltammetric method for the determination of trace gallium(III) and germanium(IV) based on the adsorption of gallium(III) and germanium(IV)-catechol complex on the cyclic renewable mercury film silver based electrode (Hg(Ag)FE) is presented. The calibration graph is linear from 1.25 nM (0.09 mu g L-1) to 90 nM (6.27 mu g L-1) with correlation coefficient of 0.999 for gallium and from 2.5 nM (0.18 mu g L-1) to 160 nM (12.3 mu g L-1) with correlation coefficient of 0.998 for germanium for a preconcentration time of 30 s. The detection limit for a preconcentration time of 60 s is as low as 25 ng L-1 for gallium and 58 ng L-1 for germanium. The proposed method was successfully applied by studying the natural samples and simultaneous recovery of Ga(III) and Ge(IV) from spiked water and sediment samples.