This study is the first to link childhood exposure to birth registration laws with longer life in old age, estimating an intent-to-treat effect of 0.08 years (about 1 month) increase in lifespan. The effect is partly driven by enforcement of child labor laws, as birth registration reduced child labor by 5 percentage points, leading to longer schooling and better protections. Combining this with earlier research suggests that those prevented from working as children due to registration laws could gain about 0.6 years (7.2 months) of additional life. The results also suggest benefits extend beyond education and child labor, including improved access to social security, legal identity, and health services, which further support longevity.