In this work, the variation in the ultrasonic attenuation of compression waves was studied as a technique to monitor the coagulation stage of milk in the cheese making process. The main difficulty found in applying this technique in the milk coagulation process was that, in the presence of gas bubbles in milk, the ultrasonic attenuation measures do not respond to the physicochemical changes generated in the process. Once the interference of gas bubbles in milk was overcome, the technique of measuring variation in the ultrasonic attenuation of compression waves showed potential to be applied in the coagulation process. With this technique, the gel cutting time can be objectively determined for different coagulation conditions. All rights reserved, Elsevier.