The title compound, {[BaPt(CN)(4)(C(12)H(26)N(2)O(4))]·0.5H(2)O}(n), is a two-dimensional coordination polymer in which the sheets are oriented approximately parallel to the (01) set of crystal planes. In the crystal structure, disordered water mol-ecules (half occupancy) connect the sheets into a three-dimensional network via inter-molecular O-H⋯O hydrogen bonds. An N-H⋯N inter-action is also present. The shortest Pt⋯Pt contacts are 7.5969 (4) Å by an inversion relationship and 7.6781 (4) Å by translation along the a axis.