Co(OH)2 nanocone arrays are prepared by a facile hydrothermal synthesis method. The Co(OH)2 nanocones are single crystalline in nature and have an average diameter of about 200 nm. The pseudocapacitive behavior of the Co(OH)2 nanocone arrays is investigated by cyclic voltammograms (CV) and galvanostatic charge–discharge tests in 2 M KOH. As cathode for supercapacitor, the Co(OH)2 nanocone arrays exhibit a capacitance of 562 F g−1 at 2 A g−1 as well as rather good cycling stability. The enhanced supercapacitor performances are due to the porous array architecture providing fast ion and electron transfer, large reaction surface area and good strain accommodation.