Objective: To describe the angiotensin converting enzyme (ACE) genotype frequencies among Omani Arabs. Method: A polymerase chain reaction (PCR) test, based on separation of different size DNA fragments, was developed to test the presence or absence (polymorphism) of a small DNA deletion in the ACE gene. The subjects were 124 Omani Arab students of Sultan Qaboos University, Muscat. Results: The frequency of the I allele was 0.29, while that of the D allele was 0.71. The gene frequency distribution did not deviate from Hardy-Weinberg equilibrium. Conclusions: The frequency of D allele among Omanis is similar to that among other Arabs and Africans, but differs significantly from that among the Japanese and Chinese.