Electrochemical deposition of Ni from a Watts-type electrolyte under the influence of high frequency ultrasound at both high (250 W) and low (5-10 W) power sonication was investigated. An improvement in the material distribution of the deposited Ni in millimeter-sized groove-features on the cathode surface was observed. A theory based on mechanical interaction between organic additives adhering to the cathode surface and ultrasonically induced streaming-phenomena is presented here to account for the observed uniform filling behaviour. The present study further indicates a correlation between fringe-patterns on the surface of the deposit and near-boundary acoustic streaming. (C) 2003 Elsevier Science B.V. All rights reserved.