The crystal structure of [Mn(C(4)H(2)N(3)O)(2)(H(2)O)(4)].2H(2)O, conventionally abbreviated [Mn(cdm)(2)(H(2)O)(4)].2H(2)O, where cdm is carbamoyldicyanomethanide, is described. The bond lengths and distances are comparable to those previously reported for the isomorphous Ni and Co analogs. Molecular units are formed by coordination of the nitrile N atoms of two cdm anions and four water molecules to the manganese(II) cation. Although these mononuclear molecular species are connected via hydrogen bonding, no magnetic ordering was observed down to 1.55 K.