This paper presents the modeling and design of one-dimensional metamaterial phase shifters (MPSs) in monolithic-microwave integrated-circuit technology based on the composite right/left-handed transmission-line approach. From a theoretical point-of-view, we show that existing design expressions are restricted to phase shifters behaving as effective media, which is the case only if sufficiently large L and C loading elements can be designed in the given technology and at the frequency of interest. Therefore, we propose new design expressions, which are exact on the basis of the circuit model of a unit cell in the structure. We show that the new expressions must be used to design integrated MPSs and the theory is verified by means of measurements of one- and two-cell phase shifters exhibiting a 0° phase shift at 17.5GHz. The designed one-cell phase shifter provides a -10-dB input return-loss bandwidth larger than 10% with phase shifts of +29° and -30° at 16.5 and 18.5 GHz, respectively. The insertion loss is -1.3 dB at the center frequency and -1.7 dB at the limit of the bandwidth.