For at least 50 years 'hygiene education' or more currently 'hygiene promotion' campaigns in schools, along with 'school sanitation' have been an unquestioned 'essential element' of water and sanitation promotion. This study describes a set of findings and conclusions that call into question the 'obvious logic' of school hygiene and sanitation promotion as currently practised. The overwhelming majority of 'trained' pupils do not in fact wash their hands with soap after using the toilet and before eating (even though the importance of such practices is well established and has almost certainly been emphasized in hygiene classes) and open defecation still appears to be relatively widespread even in intervention schools. This research therefore presents important findings for water, sanitation and hygiene in general and in the schools sector. © 2009 Practical Action Publishing.