This lab manual guides chemists through demonstrations of synergistic effects between polyelectrolytes and nanoparticles. After a short introduction into the field of polyelectrolytes and polyelectrolyte characterization, the role of polyelectrolytes in the process of nanoparticle formation is discussed in more detail. However, polyelectrolytes can directly influence the growing of nanoparticles and also can stabilize the nanoparticles formed. Therefore, the nanoparticle formation in polyelectrolyte-modified template phases, e.g. microemulsions, is of growing interest. Finally, methods for characterization of the polyelectrolyte-modified nanoparticles are explained. The adsorption of polyelectrolytes can be detected by measuring the zeta potential at the nanoparticle surface by means of electrophoretic light scattering, acoustophoresis or streaming potential measurements. It is also shown that the particle size and particle size distribution can be determined by using dynamic light scattering in combination with electron microscopy. Moreover, all methods and preparation techniques are discussed in sufficient detail to give readers deeper insight into the methodical background.