Background: Lichen planus has various clinical and epidemiologic features in different countries. Objectives: To determine clinical and epidemiologic patterns of lichen planus in dermatology department of Hamadan Sina Hospital during a ten-year period. Patients and Methods: This retrospective descriptive study was performed on 363 patients (Including 190 females and 173 males) suffered from lichen planus, referred to Hamadan Sina Hospital, during the years 1991-2001. Data were obtained from patients’ files and were analyzed by EPI6 software. Results: Among 6610 patients who were biopsied, 363 cases (5.5%) were diagnosed as lichen planus. Isolated mucous membrane involvement was observed in 36 patients (9.9%) and 9 patients (2.5%) had both skin and mucous membrane lesions. 318 patients (87.6%) had only skin involvement. The most common site of involvement was face in 71 patients (12.7%). Actinic lichen planus was the most common clinical form of lichen planus, which was seen in 126 patients (36.4%). Conclusion: Among the patients suffering from lichen planus who were biopsied, the face was the most common site of involvement and lichen actinicus was the most common clinical pattern.