The distribution of blood groups was different from place to place and may not be found in similar numbers even among ethnic groups. Frequency distribution of blood groups is important for modern medicine, genetic research, anthropology, ancestral relations of humans and forensic science. The aim of this study was to determine the allelic, genotypic and phenotypic frequency distribution of ABO and Rh blood groups among students attending in Tagel preparatory and high school in Simada woreda, Ethiopia from September to August 2020. Blood samples were taken from 384 volunteer students by finger-pricks and blood groups were determined by haemagglutination method using commercially available anti-sera A, B, and Rh (D). Descriptive statistics was used to calculate percentage frequencies of blood phenotype. The genotypic and allelic frequencies of the blood groups were calculated from the observed phenotypes under the assumption of Hardy–Weinberg equilibrium. In the ABO system, type O was the most prevalent (34.63%) followed by A (32.03%), B (23.95%) and AB the least (9.37%). In case of Rh system, most of the students were Rh+ (96.1%) and the rest were Rh-(3.9 %). The allelic frequencies of O (Io), B (IB) and A (IA) were 0.58, 0.22 and 0.19, respectively. While allelic frequencies of the Rh blood group of D and d were 0.803 and 0.197, respectively. Genotypic frequencies of OO, AA, AO, BB, BO, and AB were 0.336, 0.048, 0.255, 0.036, 0.220 and 0.084 respectively. While the genotypic frequency of DD, Dd and ddwere0.64, 0.31, and 0.039 respectively. The present study gives baseline information regarding the management of blood bank and transfusion services in the community. Large sample size with different areas is recommended to make strong generalizations. Key words: Blood group, Tagel preparatory and high school, prevalence, Rh, ABO