The title compound, C(6)H(8)NO(+).H(2)PO(4)(-), consists of 2-(hydroxymethyl)pyridinium and dihydrogenphosphate ions. The dihydrogenphosphate moieties are linked into chains by pairs of P-O-H.O-P hydrogen bonds. The 2-(hydroxymethyl)pyridinium cations are connected to the dihydrogenphosphate units by O-H.O and N-H.O hydrogen bonds. Weak pi-pi interactions help to determine the interchain packing.