Developmental and gender effects in the transmission of information about a tool-use task were investigated within a "diffusion chain" design. One hundred and twenty-seven children (65 three-year-olds and 62 five-year-olds) participated. Eighty children took part in diffusion chains in which consecutive children in chains of five witnessed two attempts on a tool-use task by the previous child in the chain. Comparisons were made between two experimental conditions in which alternative techniques were seeded and a third no-model control condition. Children in the diffusion chains conformed to the technique they witnessed, in one experimental condition faithfully transmitting a technique absent in the no-model condition. Five-year-olds displayed more robust transmission than three-year-olds, and boys were both more competent and displayed stronger transmission than girls.