Rahnavrd: Genetic and biochemical diversity of Hypericum perforatum L.- Abstract. Hypericum perforatum, also known as St John's wort, is an important medicinal plant that produces many secondary metabolites that have anti-viral, anti-bacterial, and anti-depression properties.The most effective drug substance in this plant is hypericin that changed in the various genotypes. To investigate the genetic and biochemical diversity of Hypericum perforatum, samples were collected from different genotypes around the Caspian climate region. A total of 15 genotypes from the Hyrcanian Province in the Caspian climate region were evaluated using 15 randomized amplified primers design (RAPD primers). A total number of 90 bands with the average of bands amplified by each primer was 9-band. The number of polymorphic bands per primer ranged from 1 to 13 and the bands were 250 to 3000 bp in size. Based on the results, OPAD-10 primer with 13 bands and OPV10 with 7 bands were used as the maximum and minimum number of amplified fragment, respectively. Molecular marker genotypes showed a high degree of polymorphism. Based on the RAPD results, the genotypes were divided into 4 groups. Most similar genotypes with a coefficient of 75% were in subgroup A 3 ( Noshahr and Kelardasht ) . Variation in hypericin was very significant in the genotypes grown under identical conditions. The highest amount of hypericin was measured in the Kelardasht genotype and the lowest amount in the Roodsar genotype.