The aim of the work was the synthesis of zinc oxide nanoparticles incorporated into water-based polymer systems together with assessment of their effect on the mechanical properties of the prepared nanocomposites. ZnO nanoparticles were prepared by basic precipitation of zinc salts in water. To ensure perfect compatibility with the polymeric systems and to control the particle size, the ZnO nanoparticle surface was modified by polymeric surfactants tailored for this purpose. ZnO particles were physically bonded to the water-based system via electrostatic interactions. All the composites have shown improved mechanical properties compared to the unmodified systems depending on the ZnO concentration in the water-based system.