Asthma self-management programmes have been shown to increase children's knowledge about asthma and improve their management practices and health status. However, existing programmes have rarely addressed the unique learning needs of very young children. This study aimed to develop and assess the effectiveness of a video tape and picture book designed to teach children about the prevention and management of acute episodes of asthma. The information content of the educational resources was determined by analysis of relevant medical information and asthma management skills. Social Learning Theory and consideration of the developmental stage of the target population informed the format and style of presentation of the resources. Eighty children aged between 2 and 5 years who had been diagnosed with asthma by their medical practitioner and who required daily asthma medication participated in a controlled experimental study. The study evaluated the impact of the asthma education resources on children's knowledge about asthma, compliance with medication regimens and health status. Children were randomly allocated to one of three experimental groups. Children in these groups were exposed to either the video tape alone, the book alone or both the video tape and book, or to a control group who viewed materials unrelated to asthma. The results for the three experimental groups were compared with the control group who did not receive exposure to any of the asthma education resources. The results showed that children in each experimental group had significantly greater gains in asthma-related knowledge than children in the control group and children exposed to both resources showed the greatest increases in knowledge. Children in each of the three experimental groups also had better compliance and health than children in the control group. These findings indicate that carefully designed asthma education resources are useful for providing even the youngest children with information about asthma and its management.