Summary. Several measures of quality of life (QoL) are available for children with haemophilia. However, most are not disease-specific and few focus on children's perspectives. The purpose of this study was to develop a psychometrically sound measure of QoL that included the perspectives of boys with haemophilia. A list of potential items was developed from the literature, other measures, and input from five discussion sessions with adults with haemophilia, children with haemophilia and their parents and haemophilia nurses. The list was augmented with items generated by three focus groups with children and three focus groups with parents. These groups also prioritized items and recommended a domain structure. Supplemental information was gathered by surveying haematologists. Data from all sources were analysed to reduce the number of items using a two-step approach, based on rules that weighted the children's priorities most heavily. The remaining items were compiled into a questionnaire that was pilot tested with 10 children and their parents. The total item pool contained 228 potential items. Of these, 33 were removed based on three focus groups and survey responses, 72 were removed after the completion of all focus groups and 46 were removed due to redundancy. This resulted in a 77-item version of the CHO-KLAT. Pilot testing identified the need to subdivide two items, resulting in a 79-item CHO-KLAT. The CHO-KLAT is a promising disease-specific measure of QoL that reflects children's unique perspectives. This child-centric focus distinguishes the CHO-KLAT from alternative measures of QoL. Further research will assess the measurement properties of the CHO-KLAT.