Alpha thalassemia is a common genetic disorder with more than 20% of the world population to be a carrier of some form of α–thalassemia, as estimated by The World Health Organization [1]. It has heterogeneity in its presentation and inheritance and characterised according to their deficient or absent in alpha globin chain involved [2]. The affected individuals may be asymptomatic with hypochromic microcytic anemia or in silent alpha thalassemia may have no clinical signs with normal to mild haematological changes [3]. Current voluntary thalassemia screening programme in Malaysia is mainly based on MCH level of less than 27 before molecular study for alpha thalassemia is done if Hb analysis showed normal results, to exclude alpha thalassemia. Accurate characterization of hematologic parameters is important for selection of appropriate molecular test to determine the carrier genotype, as the test is expensive, time-consuming and not always available. This study was aimed to evaluate the correlation of hematological parameters (Hb, RBC, MCV, MCH, RDW and platelet) with various types of deletional alpha-thalassemia among patients in HUSM.