PurposeThe aim is to study statural growth in a large cohort of children with chronic myeloid leukaemia (CML) treated with front-line imatinib. MethodsRetrospective data from 81 children less than 18years of age with CML identified in the French pediatric registry were analysed. Height was expressed as standard deviation score (SDS). ResultsA gradual decrease in height SDS was observed over time since starting imatinib. The height SDS was significantly lower 12months and 24months after the start of imatinib overall (p<10−4) irrespective of gender and pubertal age. The height SDS was significantly (p<10−4) lower 12months after the start of imatinib in boys and girls, and in the prepubertal age group as well as in the postpubertal age group, respectively. A similar finding was observed in the subgroups of boys and girls starting imatinib at a prepubertal or postpubertal age. Loss in height SDS 12months after the start of imatinib was of the same range in boys when compared to girls and in patients who started imatinib at a prepubertal age compared to those who started at a postpubertal age. ConclusionGrowth velocity was altered during the first years of imatinib treatment in boys as well as in girls and in prepubertal age patients as well as in adolescents.