Gilbert's syndrome is an autosomal-recessive disease characterized by elevated levels of unconjugated bilirubin. This disease is the most common hereditary cause of increased bilirubin. Hyperbilirubinemia in this syndrome, is caused by the reduced activity of enzyme glucuronyltransferase which conjugates bilirubin making it soluble in water. The prevalence of Gilbert's syndrome is 4-16%. Clinical manifestations usually occur during puberty when the concentration of steroid hormones increases the level of bilirubin in the bloodstream. This syndrome is more common in men than in women (2-7:1). Gilbert's syndrome is characterized by intermittent episodes of mild jaundice that may be caused by dehydration, stress, infections and starvation. Other symptoms are nonspecific and rare. They include diarrhea, nausea, fatigue and loss of appetite. Gilbert's syndrome is a benign disease that doesn't requires specific treatment. It is important to warn patients about medicines that may increase the serum concentration of bilirubin in the bloodstream and cause jaundice. There are also some medicines that are metabolized through enzyme glucuronyltransferase and, because of its reduced level, can have toxic effects on the body. The aim of this study was to review the frequency insertion of the TA dinucleotide in gene region UGT1A1. Patients with Gilbert's syndrome have 7 TA repeats on both alleles in UGT1A1gene region (TA7/TA7) while healthy individuals are homozygotes for TA6 alel (TA6/TA6) . Heterozygotes have both 6 and 7 TA repeats (TA6/TA7) and in most cases they will not have hyperbilirubinemia. The analysis of 1091 blood samples revealed that 136 or 12% respondents are healthy individuals with TA6/TA6 genotype, 254 or 24% are heterozygotes (TA6/TA7) and 701 or 64% are patients with 7 TA repeats on both alleles (TA7/TA7). Conclusion: Gilbert's syndrome is a benign disease that doesn't require specific treatment. It is important to warn patients on provocative factores that can lead to jaundice and also on medications that can cause hyperbilirubinemia.