The Primary School Action for Better Health (PSABH) project was first funded on a small scale by DFID in 1999, under a health umbrella programme called HIV and AIDS Prevention and Care (HAPAC). HAPAC was implemented throughout one rural region in Kenya, called Nyanza Province, which borders Lake Victoria. After initial, positive impressions the project was expanded in order to test the potential impact of a large-scale, school-based HIV and AIDS education intervention on pupil knowledge, attitudes and behaviour. The overall objective was to bring about positive, risk-reducing behaviour changes in pupils in Standards 6, 7 and 8 (approximate age range 10-16 years). This paper adresses the project methodology and design, key findings at the six-month evaluation point, and outcomes related to knowledge, attitudes and behaviour of pupils.