Trends in human welfare in Brazil have remained shrouded by a dearth of historical evidence. Although quantitative scholars have revealed the efficacy of the First Republic (1889–1930) in fomenting economic progress, the extent to which Brazil's early economic growth fostered improvements in health remains unclear. This paper fills this void in scholarship by relying on hitherto untapped archival sources with data on human stature—a reliable metric for health and nutritional status. My analysis centres heavily on a large (n ≈ 16,000), geographically-comprehensive series compiled from military inscription files, supplemented by an ancillary dataset drawn from passport records (n ≈ 6,000). I document inferior heights in the North and Northeast that predated the advent of industrialisation. At the national level, my findings reveal an increase in stature of over 2.5 cm between soldiers born in the 1880s and those born in the 1910s. In the South and Southeast, I argue that increased real income and public-health interventions explain the earlier upward trend in heights, while rural sanitary reforms were most important in the North and Northeast, where heights remained stagnant until the 1910 decade and diseases such as hookworm and malaria were most rampant.