Introduction: The human body adapts to its place of residence, but this topic has not been studied in the Peruvian working population. Objective: Determine physiological and anthropometric variations in workers due to their residence in three geographic altitudes in Peru. Methods: An analytical cross-sectional study was conducted of physiological data (6 laboratory parameters) and anthropometric data (weight and height) of 7 500 workers from three different altitudes: Lima (sea level), Arequipa (2 500 m above sea level) and Cerro de Pasco (4 300 m above sea level). The measures were standard and taken by occupational clinics with quality certifications. Coefficients and p values for differences between the altitudes were obtained and adjusted according to the sex and age of participants. Results: All the physio-anthropometric parameters varied with the altitude of the place of residence (all p values were under 0.005). The parameters which increased at a higher altitude were hemoglobin, total cholesterol and HDL cholesterol, whereas the ones which decreased at a higher altitude were weight and fasting glucose. Among men all variables increased except for HDL cholesterol (which decreased significantly) and LDL cholesterol (which did not show any statistical variation), in comparison with women. Conclusions: Variations in measurements taken from workers from different places of residence are obvious, which shows that fixed parameters should not be used for their labor assessment. This should be taken into account by occupational doctors and authorities for medical attitude assessment and occupational surveillance.