We describe a patient with acute leukemia of ambiguous lineage who had trisomy 4 as the sole cytogenetic abnormality. Clinical, pathological, immunophenotypic and molecular features are presented and compared with the previous 4 published cases. Over expression of c-kit, which is localized to chromosome 4, was documented on the leukemic blasts. Prognosis seems to be poor. Treatment with acute lymphoblastic leukemia like regimens seems to be superior compared to acute myeloid leukemia like regimens and allogeneic stem cell transplant is recommended after achieving remission.