In acute myeloid leukemia (AML), () rearrangements are among the most frequent chromosomal abnormalities; however, knowledge of the genetic landscape of -rearranged AML is limited. In this study, we performed whole-exome sequencing (n = 9) and targeted sequencing (n = 56) of samples from pediatric -rearranged AML patients enrolled in the Japanese Pediatric Leukemia/Lymphoma Study Group AML-05 study. Additionally, we analyzed 105 pediatric t(8;21) AML samples and 30 adult -rearranged AML samples. RNA-sequencing data from 31 patients published in a previous study were also reanalyzed. As a result, we identified 115 mutations in pediatric -rearranged AML patients (2.1 mutations/patient), with mutations in signaling pathway genes being the most frequently detected (60.7%). Mutations in genes associated with epigenetic regulation (21.4%), transcription factors (16.1%), and the cohesin complex (8.9%) were also commonly detected. Novel mutations were identified in 5 pediatric -rearranged AML patients (8.9%) and 2 adult -rearranged AML patients (3.3%). Recurrent mutations of (n = 3, 2.9%) and (n = 8, 7.6%) were found in pediatric t(8;21) AML patients, whereas no mutations were found, suggesting that D-type cyclins exhibit a subtype-specific mutation pattern in AML. Treatment of -rearranged AML cell lines with CDK4/6 inhibitors (abemaciclib and palbociclib) blocked G1 to S phase cell-cycle progression and impaired proliferation. Pediatric -rearranged AML patients with coexisting mutations (n = 16) had significantly reduced relapse-free survival and overall survival compared with those without coexisting mutations (n = 9) ( = .048 and .046, respectively). These data provide insights into the genetics of -rearranged AML and suggest therapeutic strategies.