Four hundred and eleven (411) confirmed hepatitis B surface antigen (HBsAg) positive individuals were tested for hepatitis delta antibodies (anti HDV) by the enzyme immunoassay method (EIA) from June 1988 through December 1993. An overall prevalence rate of 4.87% was recorded while rates for liver diseased patients, subjects on hemodialysis programs, intravenous drug addicts and blood donors showed 7.69%, 6.85%, 5.77% and 2.75% respectively. Breaking down rates according to the country of origin of our subjects showed the highest prevalence among Middle Easterners (8.22%) and Saudis (6.22%), while it was 2.63% among the India subcontinent subjects. No HDV case has been recorded from the Southeastern Asia samples despite the known higher HBsAg anemia in this region. This study could suggest that although HDV infection is limited to HBV carriers, the HDV prevalence does not seem to be a simple function of HBV, as some other factors (environmental, genetic, cultural, and/or viral strains) could modify the HDV/HBV relationship. However, limitation of the currently available tests for HDV could be the cause of the underestimation of HDV prevalence here as well as elsewhere. Ann Saudi Med 1994;14(6):503-506. This single strand RNA virus is considered as a mini-defective virus that requires a complementary helper function of hepatitis B virus (HBV) for its synthesis; hence, it can only develop in persons infected with HBV and it is well established that the HDV pathology is mainly due to its direct cytopathic effect on the hepatocytes as opposed to the immunological damage of HBV.2,3