The aim of this work is to use microelectrodes as a current approach for the study of unmediated electrochemistry of redox proteins. An electrochemical study of monohemic cytochromes c 552 from Pseudomonas nautica 617, cytochrome c 553 from Desulfovibrio vulgaris and horse heart cytochrome c is presented at inlaid disk microelectrodes of platinum, gold and carbon. Different electrochemical techniques were used such as linear scan, differential pulse and square wave voltammetry. The electrochemical response was also analyzed at conventional size (macro) electrodes for comparison. In all situations a promoter was used. The electrochemical behaviour was evaluated in terms of kinetics of the electrode processes and the formal potentials determined. Diffusion coefficients were also calculated from the voltammetric data. A critical comparison of the results obtained is carried out and the advantages of microelectrodes for electrochemical studies of metalloproteins are pointed out.