This paper introduces a complex model that describes the competition between the populations of healthy and leukemic cells and the inuence of the T-lymphocytes on the evolution of leukemia. The system consists of 5 delay differential equations derived from a Mackey-Glass approach. The main results of this work center around suffcient linear stability conditions for a nontrivial equilibrium point. These conditions arise from the construction of a Lyapunov-Krasovskii functional.