Introduction: Spirometry is used to evaluate the respiratory function, relating the spirometric values (VE) obtained with predetermined VE. By recommendation, Peru uses the Mexican American population´s equations to obtain their predetermined VE. The population that live in high altitude have higher VE than the predetermined VE. On the other hand, obese people have alteration in respiratory dynamics. In overweight people who live in high altitude, the changes in their VE are unknown, reason that motivated this research. Objective: To Compare the VE obtained in overweight population that live in high altitude with the VE predetermined by the Mexican American population´s equations. Methods: Descriptive, correlational, retrospective study. We present 329 spirometries (239 males and 90 females), with quality grades A and B, performed in an occupational clinic from Huancayo, between Februa...