The Programme for International Student Assessment (PISA) 2000 study assessed a wide range of knowledge and skills attained by 265,000 15-year-olds in 32 industrialized countries. One survey unit of the scientific literacy section addressed infection control issues, based on Semmelweis' landmark research on the causes and prevention of puerperal fever. The present report describes the questions and student performance for this infection control exercise set and evaluates performance variability between countries.