Chromosome 6q deletions are commonly found in lymphoidmalignancies such as acute lymphocytic leukemia (ALL), chroniclymphocytic leukemia (CLL), non-Hodgkins lymphoma (NHL), multiplemyeloma (MM), mantle zone lymphoma (MZL), and Waldenström'smacroglobulinemia (WM). The purpose of the current study was to assessthe frequency of 6q21 Deletion in patients with different B cell chronicLymphoproliferative disorders and to evaluate the association of thisdeletion with other prognostic criteria, Bone marrow and peripheralblood samples were used to obtain interphase chromosomes for thedetection of 6q deletion by interphase FISH in sixty three patients withdifferent B-cell chronic lymphoproliferative disorders (BCLPDs), theywere 30 patients with chronic lymphocytic leukemia (CLL)/smalllymphocytic lymphoma (SLL), 21 patients with NHL,4 patients withWaldenstrom Macroglobulineamia (WM) and 8 patients with MultipleMyeloma (MM). Results showed that 6q21 deletions in CLL/SLL groupwas found in 20%of cases. while in WM 6q deletion encountered in50%of cases, in DLBCL it was of 40% positivity , In FL it was 33.3% ,25% in MM and 20% in MCL. None of the 2 patients with spleniclymphoma (SL) or the 3 patients with unclassifiable B-NHL showeddeletion of 6q. These results can point to the importance of using 6q21deletion as a marker for minimal residual disease detection in differenthematological malignancies, monitoring of 6q21 deletion may also helpin detection of relapse prediction in BCLPDs.