The mixing angle, mass and couplings of the light scalar mesons f(0)(500) and f(0)(980) are calculated in the framework of QCD two-point sum rule approach by assuming that they are tetraquarks with diquark-antidiquark structures. The mesons are treated as mixtures of the heavy vertical bar H > = ([su][(s) over bar(u) over bar] + [sd][(s) over bar(d) over bar])/root 2 and light vertical bar L > = [ud][(u) over bar(d) over bar] scalar diquark-antidiquark components. We extract from corresponding sum rules the mixing angles phi(H) and phi(L) of these states and evaluate the masses and couplings of the particles f(0)(500) and f(0)(980). (c) 2018 The Author(s). Published by Elsevier B.V.