Unsuccessful cytogenetics (UC) in acute myeloid leukaemia (AML) patients treated on different SWOG trials was recently reported to be associated with increased age and dismal outcome. In order to ascertain whether this holds true also in unselected AML patients, we retrieved all cytogenetic reports in cases from the population-based Swedish AML Registry. Between 1997 and 2006, 1737 patients below the age of 80 years without myelosarcoma or acute promyelocytic leukaemia received intensive treatment. The frequencies of UC and unperformed cytogenetics (UPC) were 2.1% and 20%, respectively. The early death rates differed between the cytogenetic subgroups (P = 0.006) with the highest rates in patients with UC (14%) and UPC (12%) followed by high risk (HR) AML, intermediate risk (IR), and standard risk (SR) cases successfully karyotyped (8.6%, 5.9%, and 5.8%, respectively). The complete remission rate was lower in UC and UPC and HR compared with the other risk groups (P < 0.001). The overall five-year survival rates were 25% for UC and 22% for UPC, whereas the corresponding frequencies for SR, IR, and HR AML patients without UC and UPC were 64%, 31%, and 15%, respectively. In conclusion, lack of cytogenetic data translates into a poor prognosis. This article is protected by copyright. All rights reserved.