The characterization of the surface functionalization of polymer particles and subsequent grafting of hydrated polymer chains from their surface by microscopic techniques are essential to obtain reliable data about the actual morphology of the system. Since the size range of morphological features of functionalized polymer surfaces has long ago reached the lower end of the nanometer scale, classical light microscopy and dynamic light scattering have been replaced by electron and atomic force microscopy techniques which provide sufficient resolution for the visualization of nano-sized structures. Moreover, only polymer particle aggregates and fine organization of hydrated polymer chains which are not efficiently characterized by particle size measurements can be detected accurately with microscopy methods. Both solid and hydrated systems can be characterized by transmission electron microscopy and scanning electron microscopy (inc. cryo-electron microscopy (EM)) after appropriate sample preparation. Moreover, analytical EM methods allow not only for the size, shape and internal structure characterization, but also for the chemical composition with high spatial resolution.