Cobalt selenide (CoSe) nanostructures are produced via hydrothermal route from the reaction of cobalt salt and SeCl4 as precursors, in the presence of surfactant (CTAB, PVA, SDS) and reductant (N2H4.H2O). It is found that the temperature reaction, type of cobalt salt and surfactant play important roles in controlling the composition, structure, morphology and particle size of products. The experimental techniques of XRD, SEM, TEM, EDX and VSM are used to characterize the products and study their magnetic properties.