One of the challenges faced by concrete technology experts is how to use industrial waste as an additive or partial substitute for mortar. In this case, experts study and research the use of existing industrial waste so that it can be utilized, especially the sugar factory industry's bagasse ash waste material. This is one of the many solutions for handling waste in the community. Bagasse is waste produced from the sugar cane milling process after the juice is extracted. In the sugar cane milling process, there are 5 grinding processes from the sugar cane stalks until they become bagasse. The compressive strength value of normal mortar without bagasse ash waste is 1.28 kg/cm². The compressive strength value of mortar with bagasse ash waste 10% of the weight of sand is 1.57 kg/cm² which is the optimum mixture content in this mixture. The compressive strength value of mortar with 15% of bagasse ash waste from the weight of sand has a compressive strength of 0.90 kg/cm². The compressive strength value of mortar with 20% bagasse ash waste of the weight of sand has a compressive strength of 1.61 kg/cm². Mortar mixed with bagasse ash 10% of the weight of sand will increase from normal mortar. Meanwhile, mortar mixed with 15% or 20% bagasse ash tends to decrease compared to mortar mixed with 10% bagasse ash.