en Dermatology Dermatology Original Research Original Research <p> <strong>Background: </strong>The relationship between Lichen Planus (LP) and diabetes was studied previously, but the re-sults were in conflict. The aim of this study was to find the prevalence of diabetes mellitus (DM) in patients with LP among Iranian patients.</p><p> <strong>Methods:</strong> In this study, 80 patients with LP were enrolled. They referred to dermatology clinic of our hospital during one year. A self-designed checklist for the study included duration of the disease, the pattern of the dis-tribution of lichenoid lesions and fasting blood sugar (FBS).</p><p> <strong>Results:</strong> From 80 patients with LP, 16 (20%) had diabetes. Also, 14 patients (17.5%) had impaired fasting glucose. The mean age of diabetic patients was significantly higher than non-diabetic group (p=0.039). In addi-tion, the duration of LP in patients with DM was significantly higher than non-diabetic patients (p=0.024).</p><p> <strong>Conclusion:</strong> In our study, we saw a high prevalence of DM among patients with LP. Comparing our findings with the overall prevalence of DM in Iran, there was a significant difference between the prevalence of DM among patients with LP and the overall prevalence (p=0.001). Regarding our findings screening for FBS in pa-tients with LP is required in Iran.</p> Lichen Planus, Diabetes mellitus, Impaired fasting glucose. 22 26 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-283&slc_lang=en&sid=1 Najmosadat Atefi najmosadatatefi8931@yahoo.com 20031947532846007517 20031947532846007517 Yes Rasoul-e-Akram Hospital, Tehran University of Medical Sciences, Tehran, Iran Mehrdad Majedi mehrdadmajedi8931@yahoo.com 20031947532846007518 20031947532846007518 No Rasoul Clinical and Developmental Research Center (RCDRC) of Rasoul-e-Akram Hospital, Teh-ran University of Medical Sciences, Tehran, Iran. Shadi Peyghambari shadipeyghambari8931@yahoo.com 20031947532846007519 20031947532846007519 No Shahid Beheshti University of medical sciences, Tehran, Iran. Shadi Ghourchian shadighurchian@gmail.com 20031947532846007520 20031947532846007520 No Scientific Students’ Research Center (SSRC), Tehran University of Medical Sciences, Rasoul Clinical and Developmental Research Center (RCDRC), Rasoul-e-Akram Hospital, Tehran, Iran.