The mol-ecular structure of the title compound, NH(4) (+)·C(7)H(7)O(4)S(-), is featureless [the methoxy C atom deviating 0.173 (6) Å from the phenyl mean plane] with inter-atomic distances and angles in the expected ranges. The main feature of inter-est is the packing mode. Hydro-philic (SO(3) and NH(4)) and hydro-phobic (PhOCH(3)) parts in the structure segregate, the former inter-acting through a dense hydrogen-bonding scheme, leading to a well connected two-dimensional structure parallel to (100) and the latter hydro-phobic groups acting as spacers for an inter-planar separation of c/2 = 10.205 (2) Å. In spite of being aligned along [110], the benzene rings stack in a far from parallel fashion [viz. consecutive ring centers determine a broken line with a 164.72 (12)° zigzag angle], thus preventing any possible π-π inter-action.