Polyaniline spherical and cubic shells with hierarchical nanostructures were prepared by using MnO₂ hollow hierarchical nanostructures with different morphologies as reactive templates in a controlled manner. Scanning electron microscopic (SEM) and transmission electron microscopic (TEM) images reveal that the PANI shells as-prepared are narrowly dispersed and possess uniform morphologies. Fourier transform infrared (FT-IR) and UV−vis spectra of the hollow shells indicate that the PANI exists in the emeraldine form. Cyclic voltammogram shows that the PANI exhibits multiple redox behavior during potentiodynamic cycling in acidic media at potentials. This strategy developed can be extended to synthesize other conducting polymers such as PPY shells with the similar controlled 3D hierarchical nanostructures.