The present study analyzed history of smoking and willingness to quit smoking in patients referred for diagnosis and treatment of different oral mucosal lesions. Prior to the initial clinical examination, patients filled in a standardized questionnaire regarding their current and former smoking habits and willingness to quit. Definitive diagnoses were classified into three groups (benign/reactive lesions, premalignant lesions and conditions, and malignant diseases) and correlated with the self-reported data in the questionnaires. Of the 980 patients included, 514 (52%) described themselves as never smokers, 202 (21%) as former smokers, and 264 (27%) as current smokers. In the group of current smokers, 23% thought their premalignant lesions/conditions were related to their smoking habit, but only 15% of the patients with malignant mucosal diseases saw that correlation. Only 14% of the smokers wanted to commence smoking cessation within the next 30 days. Patients with malignant diseases (31%) showed greater willingness to quit than patients diagnosed with benign/reactive lesions (11%). Future clinical studies should attempt (1) to enhance patients' awareness of the negative impact of smoking on the oral mucosa and (2) to increase willingness to quit in smokers referred to a dental/oral medicine setting.