EMI radiation in an integrated circuit device package (10) is reduced or eliminated by the introduction of a magnetic material into the encapsulating medium (14). The permeance of the magnetic encapsulating medium (14) affects the inherent series inductance of the lead frame conductors (16) to thereby reduce electromagnetic interference. Ferrite microbeads (30) are formed around the lead frame conductors (16) to contain the magnetic flux (32) generated by an electrical current signal and to attenuate the effects of mutual inductance.