1) Background: Polymerase chain reaction (PCR) is a highly sensitive method to detect minimal residual disease (MRD). Although leukemia-specific translocations are detected only in minority of patients with acute lymphoblastic leukemia (ALL), several investigators developed methods to detect MRD by PCR, based on preferential usage of specific genetic elements, the limited number of VB and JB elements of T cell receptor (TCR) delta gene, and assembled V regions of immunoglobulin (Ig) gene containing re1atively conserved base sequences. 2) Methods: We evaluated antigen receptor gene rearrangement patterns of leukemic cells from ALL patients by southern blot technique, as a baseline study for the detection of MRD using PCR. 3) Results: Rearrangements of Ig heavy chain, TCR beta, gamma and delta chain gene were found in 68%, 68%, 64%, 9B% of patients respectively. So thern analysis of HindIII digests with JBS16 probe showed Vδ[Jδ] rearrangement in only 4 cases. 4) Conclusion: Heavy chain gene rearrangement is more suitable target for the application of PCR than TCR delta gene rearrangements for detection of MRD in ALL.