In this paper, a compact and low loss tunable phase shifter with low magnetic fields using partially magnetized ferrites was designed, fabricated and characterized. The new magnetic field tunable phase shifter was designed based on partially magnetized yttrium iron garnet (YIG) operating at C-band, which showed low insertion loss and a large phase shift of 350° at 6 GHz under a low bias field of 100 Oe. The tunable phase shifter also exhibited an insertion loss of 3.6 dB. The low tuning field requirement provides a unique opportunity for realizing compact tunable ferrite/piezoelectric multiferroic devices controlled by an electric field. Tunable phase shifters using partially magnetized ferrites with low magnetic fields lead to compact tunable phase shifters with low power consumption. © 2013 IEEE.