Melanin doped zinc oxide thin films were obtained using a process of soft chemistry with pH in the basic region. The electric and structural properties of these films were compared with films of un-doped ZnO obtained using the same process. Undoped films show the characteristic diffraction pattern of polycrystalline ZnO wurtzite type, while the doped films also present other signals associated to the melanin or some derived present phase of this. It is relevant because melanin is reported as amorphous material. Differences of grain size were detected and attributed to the presence of at least two existent phases in the films. Resistivity data were analyzed from the obtained values of films of un-doped ZnO and associated to the structural changes. The films have turned out to be stable in bio-generating systems of useful energy.