Modification of conventional zinc titanate (ZT) sorbents to increase their reactivity and stability during multiple cycles of sulfidation/regeneration at high and middle temperatures was pursued by addition of Co3O4. Moreover, evaluation of the modified zinc titanates (ZTC) was conducted using several instruments such as an X-ray diffractometer, Fourier transform infrared spectrometer, scanning electron microscope, and so on. The ZTC sorbents prepared by the physical mixing of the ZT sorbent with 25 wt % of Co3O4 showed an excellent sulfur-removing capacity and no deactivation even after multiple cycles of sulfidation/regeneration in both high- and middle-temperature conditions. The cobalt permeated the Zn2TiO4 lattice, leading to a new spinel phase, ZnCoTiO4. It worked not only as an active site during the sulfidation process but also as a support to prevent zinc migration to the outside of the sorbents and to minimize volume expansion/contraction. Under middle-temperature conditions, the phase separation of the ZTC sorbent including a cobalt oxide intermediate in addition to the ZnCoTiO4 spinel structure was observed. Also, the cobalt additive increased the regeneration capacity of Zn-based sorbents because it played an important role as the catalyst for oxidation.