| abstract | The mitefauna associated to Merlot and Chardonnay grapevine cultivars and associated plants in the municipalities of Bento Gonçalves and Candiota, Rio Grande do Sul was investigated. The study was developed between October 2006 and September 2007, where 20 grapevine plants were randomly chosen from each municipality and monthly sampled. Three leaves of each plant were taken. A total of 11,598 mites belonging to 14 families and to 52 species were found. Fifty-nine percent of the total specimens were collected in Candiota, being 93% associated to the Merlot cultivar. Higher species richness was observed on associated plants. Phytoseiidae showed the highest species richness, with ten species, and Eriophyidae showed the highest abundance, with 8,675 specimens. Calepitrimerus vitis (Nalepa, 1905) and Polyphagotarsonemus latus (Banks, 1904) were the most common phytophagous mites, while Neoseiulus californicus (McGregor, 1954) and Pronematus anconai (Baker ,1943) were the most common predators. |