Ferromagnetic-nonmagnetic heterogeneous alloy nanostructures are attracting growing interest because of their special physical properties, such as giant magnetoresistance effect and mixed magnetism produced by the change in structure, magnetism, or electrical transport. Here, we report a synthesis route for the preparation of CoO/ZnO alloy dendritelike structures consisting of orderly organized hexagonal nanoplatelets by electrochemical deposition in a solution of 1.0 mol/L Zn(NO3)(2)+0.1 mol/L Co(NO3)(2)+3.00 mol/L NH4F+0.1 mol/L citric acid at 90 degrees C. The main trunk and side branches of the CoO/ZnO alloy dendritelike structure are regularly angled, and each branch is made of periodic hexagonal nanoplatelets. The effects of electrodeposition parameters on the compositions of CoO/ZnO alloy dendritelike structures were studied. The morphologies of CoO/ZnO alloy dendritelike structures can be well controlled by changing deposition current densities or the concentration of Zn(NO3)(2). The formation process of the dendritelike arrangement of periodic CoO/ZnO alloy hexagonal nanoplatelets was investigated in this paper. A magnetization measurement indicates that these prepared CoO/ZnO alloy dendritelike structures have a soft ferromagnetic behavior at 120 K and a vortex magnetization at 215 K.