Oral lichen planus is a premalignant chronic inflammatory mucosal disorder with unknown etiology. It is amultifactorial disease and in addition to genetic background, infections, stress, drug reactions are suggested asrisk factors. Helicobacter pylori which is involved in development of many gastrointestinal lesions may also beimplicated in oral lichen planus induction. This is of clear importance for cancer prevention and the present studywas performed to determine any association between H. pylori infection and oral lichen planus in southwesternIran. Anti H. pylori IgG levels were determined in 41 patients and 82 sex-age matched controls. The resultsshowed no association between H. pylori infection and oral lichen planus (51% in patients vs. 66% in control).or any of its clinical presentations.