This study estimates the burden of diarrhoeal diseases caused by inadequate water, sanitation, and hygiene (WASH) practices in low- and middle-income settings. The analysis uses global exposure data from 2012 and risk estimates from systematic reviews to calculate attributable deaths and disability-adjusted life years (DALYs). In 2012, 502,000 diarrhoea deaths were attributed to inadequate drinking water, 280,000 to inadequate sanitation, and 297,000 to inadequate hand hygiene. Together, these factors caused 842,000 diarrhoea deaths, representing 1.5% of the total disease burden and 58% of diarrhoeal diseases. Among children under 5, 361,000 deaths could have been prevented, accounting for 5.5% of the total burden in this age group. The study emphasizes the importance of improving WASH in low- and middle-income settings to reduce diarrhoeal disease burden and highlights the need for better data on exposure and risk reductions.This study estimates the burden of diarrhoeal diseases caused by inadequate water, sanitation, and hygiene (WASH) practices in low- and middle-income settings. The analysis uses global exposure data from 2012 and risk estimates from systematic reviews to calculate attributable deaths and disability-adjusted life years (DALYs). In 2012, 502,000 diarrhoea deaths were attributed to inadequate drinking water, 280,000 to inadequate sanitation, and 297,000 to inadequate hand hygiene. Together, these factors caused 842,000 diarrhoea deaths, representing 1.5% of the total disease burden and 58% of diarrhoeal diseases. Among children under 5, 361,000 deaths could have been prevented, accounting for 5.5% of the total burden in this age group. The study emphasizes the importance of improving WASH in low- and middle-income settings to reduce diarrhoeal disease burden and highlights the need for better data on exposure and risk reductions.