Combined prenatal exposure to pesticides and psychosocial stressors accelerated biological aging by up to 0.41 years in South African children followed from ages 1 to 5. The study tracked 643 mothers during pregnancy, measuring 11 urinary pesticide metabolites and seven psychosocial factors including food insecurity and interpersonal violence. Food insecurity, violence exposure, and stress biomarkers contributed most to accelerated aging, with pyrethroid pesticide metabolites PBA and TDCCA also playing significant roles. This research breaks new ground by demonstrating that environmental toxins and psychosocial stress interact synergistically to age children faster than either exposure alone. The findings suggest that early-life adversity may fundamentally reprogram aging trajectories, potentially shortening healthspan and lifespan decades later. However, this preprint awaits peer review, and results may change. The study's focus on a specific South African population limits generalizability, and the observational design cannot establish causation. While epigenetic age acceleration has been linked to later-life disease risk, whether these early changes translate to actual health consequences remains unclear. This appears to be confirmatory research that reinforces growing evidence linking early adversity to accelerated biological aging.