Purpose: The aim of this study was to describe the fears of 5- to 9-year-old children related to having acute lymphoblastic leukemia (ALL) and their strategies for coping with those fears. Design and methods: The study had a qualitative descriptive longitudinal design and included a total of 35 interviews with 13 children at three different times during their treatment period. Data were analyzed using a matrixbased method inspired by the work of Miles et al. Results: Initially, most children reported a fear of needles. but during the treatment period, fewer children reported this fear. Children's coping strategies also changed over time, as they wanted more involvement and control during needle-related procedures. Other fears were having adhesive tapes removed, having a nasogastric tube, and taking tablets. During the treatment period, existential fears related to the seriousness of ALL and its consequences, such as having impaired physical fitness and being different from before and different from others, became more prominent and caused feelings of loneliness and alienation. Conclusions: The children described various fears through their treatment period, which they coped with using cognitive, emotional, and functional strategies. Over the 2.5-year period, their strategies changed. Practical implications: Because fears changed over time and varied among these different children, each child must be approached individually and attentively in every encounter.