The growth features, defect sub-structure and the influence of ion implantation on the (001) and (100) surfaces of ethylene diamine sulphate (EDS) single crystals have been studied. The surface micromorphology and defect substructure measurements of surface electrical conductivity and microhardness in both as-grown and He+ ion-implanted surfaces of EDS have also been studied. Optical and scanning electron microscopic investigations on the (001) surface of EDS revealed octogonal mother-liquor inclusions and spiral and hopper growth features. Chemical etching of the (100) surface revealed an increase in dislocation density on ion implantation, the etch pit morphology remaining the same. Studies on planar plastic anisotropy in both (001) and (100) surfaces indicated the crystallographic nature of the single crystal. Enhancement of surface electrical conductivity on ion implantation has been attributed to the formation, migration and increase in SO4− ion concentration relative to the as-grown EDS surfaces.