Abstract: The ABO and Rh blood groups are the most important blood groups despite the long list of several other blood groups discovered so far. The ABO and Rh blood groups varies worldwide and are not found in equal numbers even among ethnic groups. Therefore, this study aimed at having information on the frequencies of alleles, phenotypes and genotypes of ABO and Rh D blood groups among the major ethnic groups of Robe Secondary and Preparatory and Zebela Primary school students in Oromia region, Bale zone, Robe town. A total of 600 students were purposively selected and divided into 3 major ethnic groups i.e., Oromo, Amahara, and Wolayita, each consists of 200 students. Purposively sampled students were obtained on the basis of their willingness to participate by filling all their profile and signed on the consent agreement format. Differences in allelic, phenotypic and genotypic frequencies of the (ABO) and Rh D blood groups among the three ethnic groups of the students were observed. Blood group O and Rh (D) positive has highest allelic and phenotypic frequencies while blood group AB and Rh (D) negative has the lowest allelic and phenotypic frequencies in all the three ethnic groups. However, apart from the importance of ABO and Rh blood groups in blood transfusion practice, it is therefore imperative to have information on the distribution of these blood groups in any population group that comprise different ethnic groups.Abstract: The ABO and Rh blood groups are the most important blood groups despite the long list of several other blood groups discovered so far. The ABO and Rh blood groups varies worldwide and are not found in equal numbers even among ethnic groups. Therefore, this study aimed at having information on the frequencies of alleles, phenotypes and genotypes of ...Show More