A film was prepared from an n-butyl methacrylate/methacrylamide ethylethyleneurea (EU) copolymer [P(BMA-EU)] emulsion produced by an emulsifier-free emulsion copolymerization. The wet adhesion of the emulsion film on an alkyd resin was significantly improved by copolymerization with a small amount of EU (0.5-1.0 mol %). A sodium dodecyl sulfate emulsifier, postadded to the emulsifier-free emulsion, reduced the wet adhesion. The wet adhesion of a film prepared from a poly(n-butyl methacrylate) (PBMA)/P(BMA-EU) composite emulsion produced by an emulsifier-free seeded emulsion copolymerization with PBMA seed particles was higher than that of a P(BMA-EU) film with the same EU content. The localization of EU and the cleanliness at the particle surface were also key factors in the improvement of the wet adhesion of the polymer emulsion film. (C) 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 1825-1829, 2003.