We investigated the prognostic significance of lymphoid antigen receptor gene rearrangement in patients with newly diagnosed acute myeloid leukemia (AML). Thirty-nine patients were included in the study. Clonal gene rearrangement of immunoglobulin heavy chain (IgH) and T cell receptor beta chain (TCRbeta) was found in leukemic cells in 11 (28.2%) and 10 (25.6%) patients, respectively. Five (12.8%) had both IgH and TCRbeta gene rearrangements. Three of the seven (42.9%) B-lymphoid marker-positive and eight of the 32 (25%) B-lymphoid marker-negative patients had clonal IgH gene rearrangements. Five of the 11 (45.5%) T-lymphoid marker-positive and 5 of the 28 (17.9%) T-lymphoid marker-negative patients had clonal TCRbeta gene rearrangements. All patients were treated with similar regimens. The complete remission rate (62.5% vs 65.2%, p=1.000) and median survival (13 vs 14 months, p=0.366) were similar in patients with and without clonal IgH or TCRbeta gene rearrangements. In conclusion, while clonal rearrangements of IgH or TCRbeta genes were found in AML patients, they did not appear to effect the prognosis.