Background School-based targeted preventive chemotherapy (PC), the primary strategy for soil-transmitted helminth (STH) control, typically focusing on primary schoolchildren, was expanded to secondary school students in the Philippines in 2016. This program still excludes adults, who may also suffer from considerable morbidity and can be a significant fi cant reservoir of infection. Mass drug administration (MDA), where the entire population is treated, would bring additional health benefits fi ts but will also increase implementation costs. The incremental cost of implementing MDA for STH control compared to expanded school-based targeted PC, however, is unknown. Methods A cost survey was conducted in Zamboanga Peninsula region in 2021 to estimate the economic and fi nancial cost of implementing MDA compared to the expanded school-based targeted PC from a government payer perspective. A budget impact analysis was conducted to estimate the fi nancial cost to the government of implementing MDA over a fi ve-year timeframe. Monte Carlo simulation accounted for uncertainty in cost estimates. Costs were reported in 2021 United States Dollars ($). Findings The economic cost of MDA was $809,000 per year (95% CI: $679,000-$950,000) - $950,000) or $0.22 per person targeted (95% CI: $0.19-$0.26), - $0.26), while the expanded school-based targeted PC would cost $625,000 (95% CI: $549,000-$706,000) - $706,000) or $0.57 per person targeted (95% CI: $0.50-$0.64). - $0.64). Over fi ve years, the fi nancial cost to the government for MDA would be $3,113,000 (95% CI: $2,475,000-$3,810,000); - $3,810,000); $740,000 (95% CI: $486,000-$1,019,000) - $1,019,000) higher than expanded school-based targeted PC. Interpretation Implementing MDA in the region will increase the economic and fi nancial costs by 29% and 31%, respectively, when compared to expanded school-based targeted PC. Implementing MDA would require the Department of Health to increase their total expenditure for STH control by 0.2% and could be key in addressing the ongoing STH burden. Copyright (c) 2024 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).