Magnetic field and thermal loads are present in the operating environment of jet engine parts such as turbine rotors. Therefore, their influence on the burst velocity of rotors is worthy of investigation. The present paper addresses the analysis of rotational elastic instability in heterogeneous disks having variable thickness under magnetic field and thermal loading. Inclusion of the radial displacement in the centrifugal force indicates rotational instability at certain angular velocities. Closed-form expressions for the displacement and stresses are not possible due to variable material properties, thickness profile, thermal expansion, and conduction coefficients of the disk. The Complementary Functions Method is adopted as a numerical solution scheme. The results are obtained in terms of nondimensional parameters to achieve high accuracy with few collocation points. The burst velocities under influences of magnetic field and thermal loads are calculated. Redistributed hoop stresses are also plotted against angular velocity for different magnetic intensity and temperature changes. It is concluded that magnetic field has a stabilizing effect on the rotating heterogeneous disk and the influence of thermal load is negligible in the rotational stability analysis.