Myelodysplastic syndrome (MDS) is recognized as a preleukaemic disorder with a variable risk of transformation to acute myeloid leukaemia. Usually the blast cells in leukaemia are transformed after MDS displays a myeloid phenotype. Even though lymphoid progression had been reported previously, most displayed myeloid-lymphoid hybrid or early B phenotype. We report a case of an elderly man who had MDS transformed into Acute Lymphoblastic Leukaemia (ALL:L3) which is a rare lymphoid transformation.