The possible utility of selected compositions in the systems sro- zro2-mgo and sro-zro2-dolomite for commercial refractory products was confirmed in this study. Specifically, the compositions of interest are located in the subsystems srzro3-zro2-mgo and srzro3- zro2-dolomite. Both subsystems have regions that are not affected by hydration, but the subsystem srzro3-zro2-mgo has a larger candidate compositional region. Solid-state phase relations were determined for the subject systems over the temperature range 1,600 deg. to 1,300 deg. C, with compatibility diagrams presented for each. The systems appear to show good refractory character with no apparent low melting compositions. Because the compositions of commercial interest lie mostly in the higher zr02 portion of each system, information is presented regarding the firing treatment required to develop stabilized cubic zro2. A list of suggestions for further study of these systems, to further delineate the characteristics required for possible commercial utilization, is presented.