The objective of this study investigated the distribution of immature dendritic cells (DCs), Langerhans cells and plasmacytoid DCs in oral submucous fibrosis (OSMF), OSMF associated with oral squamous cell carcinoma (OSMF-OSCC), oral leukoplakia (OL), and oral squamous cell carcinoma (OSCC). Fourteen cases of OSMF, 9 of OSMF-OSCC, 8 of OL¸ 45 of OSCC and 8 of normal epithelium were retrospectively retrieved and their diagnoses confirmed. Immunoreactions against CD1a, CD207 e CD303 were performed and the number of positive cells quantified. A significant decrease of CD1a+ was found in OSMF (p?0.05), OSMF-OSCC (p ? 0.01), and OSCC (p ? 0.001) when compared to normal epithelium. For CD207+ the significance decrease was observed in OSMF-OSCC (p ? 0.05), and OSCC (p ? 0.01) when compared with normal epithelium, and in OSMF when compared with OL (p ? 0.05). There was no significant difference for CD303, but increased in CD303+ was observed in OSCC when compared with normal epithelium. The decrease in the number of CD1a+ and CD207+ cells may be associate to the development of oral OSCC, and in OPMDs they might be indicators of malignant transformation.