The electrodeposition of silver on platinum from ammonium-buffered solutions containing HEDTA (N-(2-hydroxyethyl)ethylenediaminetriacetic acid) at various concentrations was investigated. Potentiometric titration and voltammetric studies indicated that in the presence of 2.0 x 10(-1) M HEDTA, the deposited silver was reduced from a mixture of [AgHEDTA](2-) and [Ag(NH3)(2)](+) complexes, whereas at 2.0 x 10(-2) M and 2.0 x 10(-3) M HEDTA in the electrolyte, the silver was reduced from the [Ag(NH3)(2)](+) complexes alone. Hydrodynamic studies showed variation in the diffusion coefficient for the electroactive species in solution, depending on the HEDTA concentration. Chronoamperometric study in a solution containing 2.0 x 10(-1) M HEDTA at low overpotential (0.000 V to -0.050 V) showed a transition from progressive to instantaneous nucleation in a single current transient, whereas, at -0.200 V only 3D-progressive nucleation controlled by mass transport was observed. Scanning electron microscope images showed that the silver films produced in silver baths with HEDTA were uniform, without cracks, and fine-grained, regardless of its concentration, while in the absence of HEDTA the morphology was rough and dendritic. X-ray diffraction analysis of the films obtained at various HEDTA concentrations revealed polycrystalline silver, similar to film obtained in cyanide and EDTA/ammonia baths.