This research addresses the replacement of cement by an untreated waste from the petrochemical industry. The effects of partial replacement of cement by spent fluid cracking catalyst (SFCC) on properties of mortar were determined. In this study, a series of mortar mixes was prepared with replacement ratios of 0%, 3%, 6%, and 12%. Furthermore, performance enhancing factors such as SFCC treatment or use of plasticizers were avoided. Workability, compressive strength, and durability related properties were assessed. An improvement regarding resistance to chloride penetration was observed, as well as that, when curing in salt water, the use of SFCC may be advantageous regarding compressive strength.