In the title compound, [Cd(C2H8N2)2(H2O)2](C10H8NO3S)2.2H2O, the CdII atom, located on an inversion centre, has a distorted octahedral coordination geometry formed by two ethylenediamine and two water molecules. 4-aminonaphthalene-1-sulfonate acts as a counter-ion to balance the charge, and two antiparallel anions showing strong pi-pi stacking interactions are linked by paired N-H...O(sulfonate) hydrogen bonds into an isolated R2(2)(16) dimer. The crystal structure is stabilized by the pi-pi stacking interactions and hydrogen bonds.