Although Iran represents one of the presumed centers of domestication of grapevines, there is a huge paucity of knowledge on yeast species diversity on grapevines in Iran. This study was performed to explore the species diversity amongst the epiphytic and endophytic yeast community on grape berries in Iran. Five different regions were selected for sampling. Out of 59 collected samples, 352 yeast isolates were recovered, of those 315 isolates were epiphytes and 37 isolates were endophytes. Species were identified by a combination of M13 fingerprinting and sequencing the D1/D2 region of 26SrDNA. Twenty three different species were identified as epiphytes and 74% of them were Ascomycota. Among these species, seven (all ascomycetous) were also isolated as endophytes. Hanseniaspora uvarum was the predominant species both in epiphyte and endophyte detection and had the highest biodiversity (H’) and evenness index (E). Other species such as Pichia terricola, Metschnikowia sinensis and Aureobasidium pullulans were the further most frequently isolated species. This is the first report of Candida membranifaciens as inhabitants of grape berries.