The t(8;21)(q22;q22) is the most common translocation in acute myeloid leukemia (AML). We describe the clinicopathologic and cytogenetic profile of 117 patients with t(8;21) AML. There were 76 males and 88 adults. The median age was 26 years. Most patients (80%) had AML M2. Dysplasia was present in 68% of patients and eosinophilia in 18%. Eight patients had fewer than 20% blasts. Additional chromosomal aberrations were seen in 103 patients (88%) with loss of a sex chromosome (LSC) in 78 patients (66%) and deletion 9q in 21 (18%). The other recurrent abnormalities were trisomies 4, 8 and 15, monosomy 17 and deletion 7q (less than 5% each). Three- or four-way variant t(8;21) were seen in 6% of patients and 3% had tetraploidy. Aberrant expression of CD19 was seen in 54% of patients. FLT3 mutations were seen in 7.5% of patients (3/40) and c-KIT mutations in 6.6% (2/30). None had NPM1 or JAK2 V617F mutations. One patient had a granulocytic sarcoma. Complete remission was achieved in 96% of the 26 newly diagnosed patients after first induction. The median follow-up was 25 months (range 4-68). The overall survival was 69% at 31 months.