In this report, several materials such as M/glass (M = Cu, Ru, Ag and Pt) and Pt/Si were investigated to test their suitability for studying the early nucleation stage and growth of cobalt clusters. It was found that most of these materials stand as good substrates to be used in the study of the nucleation and growth of electrodeposited cobalt from aqueous solution containing CoSO4, CoCl2, Na2SO4 and H3BO3. Among theses substrates, Ag shows a transition from instantaneous to progressive nucleation. In the other hand the cobalt electrodeposited on Cu, Ru and Pt substrates followed progressive nucleation. Pt/Si substrates gave short transient time at maximum transient current and instantaneous cobalt nucleation on it surface. (C) 2007 Elsevier B.V. All rights reserved.