Celestite is the main source of strontium containing chemicals and metallic strontium. Unlike other sulfate containing minerals, celestite is not soluble in water. Further processing of SrSO4 requires conversion to water- soluble strontium sulfide (SrS). In this study, solubility of SrS in distilled water is investigated. SrS used in experimental study was obtained by roasting celestite at 1050 degrees C in a lab-scale rotary furnace. Experiments were carried out to determine the effects of time (90, 120, and 150 min), solid/liquid (S/L) ratio (1/5, 1/10, and 1/25 w/v) and temperature (25, 55, 75, and 95 degrees C). Stirring speed (500 rpm) was constant. XRD results of leach cakes showed that increasing temperature increases dissolution rate and efficiency. However, increasing S/L ratio decreases the leaching efficiency.