To investigate the unwanted deposition of polymers on heat transfer surfaces (polymerization fouling) the deposition of a vinyl acetate/vinyl ester copolymer during emulsion polymerization is investigated. The aim is to identify fundamental differences to the fouling behavior of an already reacted vinyl acetate/ethylene copolymer. For a qualitative comparison the surface coverage is observed using a digital microscope. For the quantitative examination the fouling resistance is calculated from the mass and the layer height of the deposited material. The degree of polymerization has a significant influence on the deposition behavior. The already reacted material system shows a larger fouling mass and a more pronounced, crater-shaped surface coverage, whereas during polymerization fouling a clearly optically different drop-shaped surface coverage was formed.