Background: Preventive chemotherapy (PC), the large-scale administration of anthelminthics, is recommended by the World Health Organization (WHO) for the control of soil-transmitted helminthiasis (STH). Since 2010, donated anthelminthics for STH have boosted the implementation of PC programmes in children, achieving global coverage of more than 60% in 2015. The WHO Global Health Estimates attribute an annual loss of over 3.3 million disability-adjusted life-years (DALYs) to STH. The aim of this study is to estimate the impact of PC programmes on child morbidity. <p> <p/> Method: We used data from the WHO Global Health Estimates, national coverage data on PC and the results of an evaluation of the impact of PC in 17 countries on morbidity previously conducted by our group. <p> <p/> Results: We estimated that the implementation of PC averted in 2015 over 44% of the DALYs that would have been caused in children by STH without the control intervention. A reduction in morbidity of over 75% is expected, if the global target is reached in 2020. If the programme is subsequently maintained, morbidity from STH will be almost totally removed by 2025. <p> <p/> Conclusions: In endemic areas, preventive chemotherapy provides a significant health benefit. We consider this estimation potentially useful to evaluate the cost utility of the investment made by several endemic countries on PC to control STH.