Mochi is a traditional snack with sticky, chewy, and soft texture made from glutinous rice. Mochi is usually cooked with conventional stove, but microwave can also be used. Eucheuma cottonii is one of gel-producing algae and can be utilized to enhance mochi texture, in form of seaweed flour or semi refined carrageenan. This research was carried out to study the effect of cooking method and adding of seaweed flour or semi-refined carrageenan towards physical, chemical, and organoleptic characteristics of mochi, and to study the effect of temperature towards physical and chemical characteristics of mochi during storage. The effect of cooking method (microwave and conventional stove) and addition of seaweed flour or semi-refined carrageenan (1.5%, 3%, 4.5%, 6%, and 7.5%) on the mochi were performed. The result shows that the appropriate treatment to make the bes3 -/'*+ &%2)( /. 0%.),+2324 %'')03%.') was adding of 1.5% seaweed flour with microwave cooking and 1.5% semi-refined carrageenan with microwave cooking. Both mochi had greater chewiness and better texture in compared to commercial mochi based on paired comparison test. Those two types of mochi were stored in two different temperatures (room and chilling temperature) for a week and were analyzed for their texture profile and water activity on a daily basis. The result shows that mochi stored in room temperature degrades faster in terms of texture (hardness and chewiness) compared to mochi stored in chilling temperature.