Abstract: | We present the possible mixing effects associated with the low-energy limit of a Standard-Model extension by two abelian gauge groups U1(1)×U2(1). We derive general formulae and approximate expressions that connect the gauge eigenstates to the mass eigenstates. Applications using the well-studied groups UB(1), U(1)B−L, U(1)Lα−Lβ (Lα being lepton flavor numbers), and UDM(1) (a symmetry acting only on the dark matter sector) are discussed briefly. |