Background Polymorphisms in the low-density lipoprotein receptor (LDLR) and apolipoprotein B 100 (APOB-100) genes have been linked to severe hypercholesterolemia in several populations. This study investigated the frequency of LDLR-Ava II and APOB-Xba I polymorphisms among Kurdish patients with severe hypercholesterolemia. Methodology We investigated LDLR-Ava II and APOB-Xba I gene polymorphisms in Kurdish patients attending the Duhok Specialized Laboratory Center in Duhok, Kurdistan Region, Iraq. We included a total of 80 subjects in this study, of which 40 (20 males and 20 females) had severe hypercholesterolemia, and 40 apparently healthy volunteers (21 males and 19 females) had normocholesterolemia, served as a control group. We used the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique to determine the polymorphisms of the LDLR-Ava II and APOB-Xba I genes. Results In those with severe hypercholesterolemia, the observed allele frequencies were AA LDLR-Ava II polymorphism (eight, 20%) followed by TT APOB-Xba I polymorphisms (six, 15%), whereas these frequencies were five (12.5%) and one (2.5%) in those with normocholesterolemia, respectively. The AA genotype group had considerably higher cholesterol and LDL-C levels compared with the GG genotype group. A similar pattern was observed when comparing the TT and CC genotype groups. Conclusions Our results showed a high frequency of AA LDLR-Ava II polymorphism in conjunction with TT APOB-Xba I polymorphism which may be strongly associated with hypercholesterolemia in the Kurdish population.