T-cell acute lymphoblastic leukemia (T-ALL) is a hematologic malignancy that accounts for 25% of adult and 15% of pediatric acute lymphoblastic leukemia (ALL) cases. Relapsed or refractory T-ALL is difficult to salvage with chemotherapy, which causes long-term toxicity, and is often fatal. The JAK/STAT and BCL-2 pathways are upregulated in T-ALL and promote increased T-ALL proliferation and survival. Currently, targeted therapies of the JAK/STAT and BCL-2 pathways have not been investigated in combination. I propose that dual inhibition of the JAK/STAT and BCL-2 pathways, with ruxolitinib and venetoclax respectively, will lead to maximal T-ALL cell death. Jurkat cells were treated with single doses of ruxolitinib (0.156µM - 5µM) or venetoclax (1.56nM - 50nM) in vitro, and analyzed by trypan blue exclusion, MTT and flow cytometry at 24, 48 and 72h post-treatment. Results demonstrate decreased proliferation by MTT, decreased viability by trypan blue exclusion, and increased apoptosis by flow cytometry for the three highest doses of ruxolitinib (1.25µM, 2.5µM and 5µM) and venetoclax (12.5nM, 25nM and 50nM). A synergistic effect was achieved for all three assays at 48 and 72h when cells were treated with a combination dose of ruxolitinib (1.25µM) and venetoclax (25nM; CI Citation Format: Kirsti L. Walker, Sabrina A. Kabakov, Fen Zhu, Sydney L. Olson, Lixin Rui, Christian M. Capitini. CXCR4 blockade of T cell acute lymphoblastic leukemia causes systemic disease in an NSG model allowing ruxolitinib and venetoclax to synergistically treat cancer burden [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2975.