Ozone is a viable alternative to sanitization of agricultural products due to its highly oxidative capacity , rapid degradation and absence of residues in food and even in the environment. Thus, this work was developed aiming to design and construct an ozone application system to investigate possible reduction on lettuce ( American variety) leaves surface at temperatures of 5° C , 15 °C and 25 °C. At the end of the storage period the greater efficiency in ozone is in 3 ppm.