This article focuses on trends in the adult heights of various sectors of Mexican society between 1850 and 1950 as a proxy for their biological and material standards of living. The evolution of biological standards of living is an alternative way to assess whether or not economic development after 1850 was beneficial to the population, using a proxy that relies on a basic natural characteristic, adult height. The recruitment records of the Mexican rural and federal militia provide us with information on the secular trends of heights of the Mexican labouring classes, while a database of passport applications allows us to compare the evolution of living standards across social classes. It is argued that the benefits of industrialisation and improved economic performance fostered by the Díaz regime (1876–1910) did not have a favourable impact on the biological wellbeing of the labouring population. There are, however, signs of improvement in living standards with the launching of welfare programmes at the end of the Cárdenas administration. In contrast, the average height of the elites increased throughout the period, suggesting that there was a growing disparity in the evolution of living standards between social classes.