The double-diffusive convection in an Oldroydian viscoelastic fluid is mathematical investigated under the simultaneous effects of magnetic field and suspended particles through porous medium. A sufficient condition for the invalidity of the 'principle of exchange of stabilities' is derived, in the context, which states that the exchange principle is not valid provided the thermal Rayleigh number R, solutal Rayleigh number RS, the medium permeability P1 and the suspended particles parameter B are restricted by the inequality BP1/π2 (R+RS) < 1.