Cytogenetic, biomolecular, and clinicopathologic features were retrospectively studied in 34 adult patients with acute myelogenous leukemia expressing one or more of the following lymphoid-associated markers (LMs): CD7, CD2, CD10, CD19, CD22, TdT. Six patients showed 11q23 rearrangements (group I); three patients had the classic Ph chromosome (group II); 15 patients had aberrations of the myeloid type (group III), including four patients with structural aberrations of 13q or trisomy 13, three patients with 7q and 1q anomalies, and two patients with trisomy 11q. Ten patients had a normal karyotype (group IV). Anomalies exclusively associated with lymphoid malignancies were not seen. Ig H and/or T-cell receptor genes were found to be rearranged in 50% and 66% of patients in cytogenetic groups I and II, respectively, versus 8% in group III and 12% in group IV. Likewise, more than one LM was more frequently detected in groups I and II. In group III, two of four patients with aberrations of chromosome 13 expressed two or more lymphoid features. Clinically, patients belonging to cytogenetic groups I and II were generally young, presented with a high white blood cell (WBC) count, and had a low complete remission rate. Survival in Ph chromosome-positive cases was uniformly short. We conclude that although there is no cytogenetic anomaly specifically associated with acute myelogenous leukemia expressing LM, a Morphologic, Immunologic, and Cytogenetic classification may constitute a working basis for further studies aimed at a better definition of clinicopathologic features and optimal treatment strategies for these leukemias.