Luminescent polymer latexes loaded with lanthanide complexes have been synthesized by miniemulsion polymerization. A self-assembled europium complex was embedded into poly(methyl methacrylate) nanoparticles without covalent linking and compared to a commercially-available neutral chelate. The nature of the surfactant was found to have a great impact on the incorporation process for the europium complex and only the latexes stabilized by a cationic surfactant exhibited a luminescence signal. A maximum doping level of about 2% in weight in the final monodispersed particles was obtained. The resulting polymeric luminescent nanoparticles showed good stability over leakage. The described synthetic method was used to incorporate multiple lanthanide complexes into latex nanoparticles affording multicolour nanolabels. Two series of polymeric latexes bearing codes are presented in this work. © 2013 The Royal Society of Chemistry.