In New Zealand and Japan, despite health education on food, exercise, and hygiene, children's health is an important concern in preschools. This study investigated the relationship between children's health and health education in New Zealand and Japan using a qualitative interpretative descriptive design method and semi-structured interviews with preschool teachers. Major children's health issues identified by preschool teachers in New Zealand were asthma, allergies, and dental hygiene. Although few preschool children are overweight in New Zealand, it becomes a serious concern in primary school. Identified as a suspected cause of children's health problems was parents providing their children with sweet and/or unhealthy foods. Preschool teachers want parents to understand and implement health education, and they stated that parents' education was necessary. In Japan, children's health problems identified by teachers were allergies, food preferences, and sleep deprivation. The suspected causes included too much convenience, parents' irregular lifestyles because they were busy, and parents' depending on preschools to discipline children in ways that should be done at home. The goals for preschool health education were similar in New Zealand and Japan. The goals should be to obtain lifelong health knowledge, an ability to make wise health-related decisions in adulthood, and healthy lifestyle choices for themselves and their families. Some children's health issues were beyond the scope of the abilities of individual preschools. Therefore, the entire nation and government should work together to cope with children's health issues and health education.