Burning mouth syndrome (BMS) is characterized by a burning sensation in the oral cavity although the oral mucosa is clinically normal. The syndrome mostly affects middle-aged women. Various local, systemic and psychological factors have been found to be associated with BMS, but its etiology is not fully understood. Oral complaints and salivary flow were surveyed in 669 men and 758 women randomly selected from 48,500 individuals between the ages 20 and 69 years. Fifty-three individuals (3.7%), 11 men (1.6%) and 42 women (5.5%), were classified as having BMS. In men, no BMS was found before the age group 40 to 49 years where the prevalence was 0.7%, which increased to 3.6% in the oldest age group. In women, no BMS was found in the youngest age group, but in the age group 30 to 39 years the prevalence was 0.6% and increased to 12.2% in the oldest age group. Subjective oral dryness, age, medication, taste disturbances, intake of L-thyroxines, illness, stimulated salivary flow rate, depression and anxiety were factors associated with BMS. In individuals with BMS, the most prevalent site with burning sensations was the tongue (67.9%). The intensity of the burning sensation was estimated to be 4.6 on a visual analogue scale. There were no increased levels of depression, anxiety or stress among individuals with more pain compared to those with less pain. It was concluded that BMS should be seen as a marker of illness and/or distress, and the complex etiology of BMS demands specialist treatment.