Chronic myelo-monocytic leukemia (CMML) is an aggressive myeloid neoplasm with some features of a myelodysplastic syndrome (MDS) and others of a myeloproliferative neoplasm (MPN). Rarely, patients with CMML have a co-existing lympho-proliferative disorder (LPD). In most cases, the lymphoid neoplasm is diagnosed first, and the CMML is considered to be a secondary therapy-induced form of leukemia. We report herein a unique case of de-novo CMML, with an underlying clonal T-cell population and describe its clinical presentation and laboratory findings. A 70-year old male presented with a 3-month history of cough, dsypnea, abdominal distension, and low-grade fever. Physical and radiological examination revealed hepatosplenomegaly but no lymphadenopathy. Peripheral blood had absolute monocytosis with marrow showing CMML with 10% blasts along with dysplasia in myeloid and erythroid lineages. Flow cytometry indicated possibility of chronic myelo-monocytic leukemia with 13% monocytic cells along with an additional clonal population of gamma/delta T cells (15%) with aberrant immunophenotype. Polymerase chain reaction (PCR) analysis was positive for clonal T-cell rearrangement. A diagnosis of CMML with an underlying clonal T-CLPD was made. The synchronous occurrence of CMML and T-cell neoplasm may be attributed to a genetic mutation common to both. Currently, there are no treatment guidelines for group of patients; hence individualized therapeutic strategies should be implemented to enable symptomatic improvement and provide optimum care.