The title compound, [Cu(2)(OH)(2)(C(6)H(16)N(2))(2)(H(2)O)](BF(4))(2), consists of dinuclear centrosymmetric [Cu(2)(OH)(2)(tmen)(2)(H(2)O)](2+) complex cations (tmen = N,N,N',N'-tetra-methyl-ethane-1,2-diamine) and tetra-fluoridoborate anions. In the cation, the Cu(II) atom shows a slightly distorted square-pyramidal coordination geometry provided by a pair of μ-OH(-) anions and by the N atoms of a chelate tmen ligand in the basal plane. The apical position is statistically occupied by the O atom of a half-occupancy water mol-ecule. The F atoms of the anion are disordered over three sets of sites with occupancies of 0.598 (9):0.269 (6):0.134 (8). The crystal packing is governed by ionic forces as well as by O-H⋯F hydrogen bonds.