In Saudi Arabia, the prevalence of sickle cell disease (SCD) varies significantly in different regions of the country, with the highest prevalence is in the Eastern province, followed by the southwestern provinces. In addition, sickle-cell trait range was reported from 2% to 27%, and up to 2.6% have SCD in some areas. The aim of this study was to assess the haemoglobin S variant among Saudi’s who aged between 19 to 40 years old, in Taif city. The result of this study showed that the heterozygous form of Hb S was detected as the major abnormality with 96% while, the result of this study was also reported three cases with 4% of adults diagnosed with Hb S homozygous. Clear understanding the genetics and the prevalence of these disorders will provide opportunities for prevention or and reduce the incidence. Thus, this study suggests that in addition to the huge efforts already accomplished by the Saudi Ministry of Health to prevent at-risk marriages, the early diagnosis for these disorders might be offered for young adults as they can discuss the issue in the early stage of the marriage proposal.