Composites with conducting polymers (ICPs) as a matrix were electrodeposited on anodes of platinum or carbon black filled polypropylene from a stirred electrolyte with dispersed particulate materials (concentration c(E)) such as copper phthalocyanine or carbon black (CB). The solvent (H2O or CH3CN) contained the monomer (pyrrole or bithiophene) and the supporting electrolyte, 0.1 M LiClO4. The concentration c(C) in the composite increases in proportion to log c(E), starting from a threshold value c(E,O). c(C)-Values of 2-60% are found, depending on the nature of the dispersed material; c(E,O) varies widely, from 1 mg dm(-3) to 1 g dm(-3). A codeposition mechanism could be derived, consisting of two steps: I. Temkin type strong adsorption of the particle and II. charge transfer. II was treated as an activated, potential dependent process. In case of the polypyrrole/CB-composite c(C) decreases with increasing BET-surface. This is rationalized in terms of a synchronous charge of the electrochemical double layer capacitance of the CB particles. PPy as a matrix is superior over polybithiophene, were oligomers are dissolving. High insertion rates (c(C)) are obtained in comparison to other systems.