Indonesia is one of the ten largest tea-producing countries in the world, with a plantation area of 104,420 hectares and a production of 139,285 thousand tons in 2018. Blister blight can cause massive crop losses across tea-growing regions of Asia, particularly in India, Sri Lanka, Indonesia, and Japan. The infection causes a 40% yield loss. The study aimed to determine the genetic diversity in Exobasidium vexans, that cause blister blight based on polymerase chain reaction-random amplified polymorphic DNA (PCR-RAPD). Sampling was conducted at Pagilaran, a tea plantation located in Central Java, Indonesia, with sampling based on altitude, Andongsili (>1,000 meters above sea level [masl]), Kayulandak (±1,000 masl), and Pagilaran (<1,000 masl) with clones TRI 2024, TRI 2025, Gambung 3, Gambung 7, Gambung 9, and Pagilaran 15. This study used the PCR method using internal transcribed spacers (ITS) 1F and ITS 4 primers. Four primers used in PCR-RAPD were OPA-02, OPA-03, OPA-05, and OPB-17. The characteristics of E. vexans , observed were ellipse-shaped basidiospore, hyaline, unicellular with one septate, formed at the tip of the sterigma with hyaline and elliptical shapes, with a range size of 7–15.5 μm x 2.3–4.5 μm. PCR-RAPD method was able to show the diversity of E. vexans , samples between clones, in which three clusters were formed at a coefficient of 0.63. Cluster I consisted of TRI 2024 Andongsili and PGL 15 Pagilaran; Cluster II consisted of TRI 2025 Andongsili and Gambung 3 Andongsili; Cluster III consisted of Gambung 7 Andongsili, Gambung 7 Kayulandak, and Gambung 9 Andongsili.

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