Objective To introduce the laboratory and clinical characteristics of acute lymphoblastic leukemia accompanied by the karyotypic abnormality of 5q-.Methods Report the diagnosis and treatment of one case of acute lymphoblastic leukemia with 5q- and review the relevant literatures.Results The patient came to the hospital because of bellyache and ostalgia.The blood routine showed a high WBC count and reduced platelets.Bone marrow aspirates examination indicated acute leukemia and by peroxidase staining and flow cytometry test,acute pro-T lymphoblastic leukemia was diagnosed.The karyotype and fluorescence in situ hybridization analysis showed 5q-.The hyper-CVAD regimen induced a temporary remission but it did not work anymore after the relapse nor did the MEA regimen.From the literatures ever reported,the kyryotypic abnormality of 5q- was rarely seen in acute lymphoblastic leukemia.In such cases,the minimal deletion region overlaped between marks of D5S410 and D5S436 corresponding to chromosomal location 5q31-33.Conclusion 5q- is rare in acute lymphoblastic leukemia and more features are still to be found about the kind of disorder.