Anthropometric studies have given much attention to the impact of industrialization and urbanization on the biological standards of living of urban populations. Instead, we know less about the evolution of height and the disparities within the rural world and how they have changed during the modern economic growth process. This article analyzes the evolution and the determining factors that would explain the inequality of the biological welfare of a group of rural populations in Mediterranean Spain. Using a database of the heights of military conscripts (N = 146,041) of the study area, a comparison is made of the biological well-being of the cohorts born between 1840 and 1965 in different rural environments (irrigated vs. dry farming). The results show that the recruits residing in irrigated areas were taller than those in dry farming areas and that the nutritional differences were greater among the latter. The advantage of the heights in irrigated areas widened with the development of commercial agriculture at the end of the nineteenth century and, although it began to reduce from the early decades of the twentieth century, the anthropometric gap persisted throughout the period analyzed. The data also suggest that the distribution of income was also more unequal in the dry farming areas, where the diet was less varied and rich than in the irrigated areas. This situation could be largely explained by the existence of low productivity agriculture in these dry farming areas, among other possible factors.