In 1995, China implemented the national program of regulating salt to contain iodine, a key micronutrient in development of cognitive ability. After the adoption of the new salt, individuals’ access to iodine improved dramatically. We compare human capital developments between cohorts born before and after the salt iodization in areas with varying pre-intervention iodine deficiency prevalence (goiter rates). For females, educational attainment for cohorts who benefited from iodized salt went up by 6%; cognitive ability measured by standard math and verbal tests also rose by roughly 6%. Yet, we don’t find significant effects for males. We also find evidence suggests that parents’ investment can partly mitigate the early-life disadvantage. Joint with Maarten Lindeboom.