RESUMEN
To document the distribution of the ABO and rhesus Rh blood groups in a random sample of Saudi students from the King Khalid University, Abha, Kingdom of Saudi Arabia, and to compare our results from that of other studies in the Kingdom and elsewhere. The subjects included in this study were 944 males from thesouthwest region of Saudi Arabia including Aseer, Jizan, and Najran regions. The ABO blood groups and Rh factor from 944 Saudi males were determined. The frequency of ABO blood groups and Rh status were calculated separately. This study was carried out at King Khalid University, Abha, Kingdom of Saudi Arabia, from January to March 2008, and the ethical approval was obtained from the Research Ethical Committee, College of Science, King Khalid University. The frequencies of ABO groups showed 56.8% for group O, 33.4% group A, 6% group B and 3.8% group AB trend. Only 7.2% of them were found to be Rh-negative. The frequencies of ABO and Rh phenotypes in the southwest population of Saudi Arabia are similar to those reported in most areas of the Arabian Gulf region