Nitric oxide, produced by inducible nitric oxide synthase (iNOS), has been implicated in the pathogenesis of periapical inflammatory, lesions (PILs); however, its existence in pericoronal dental follicles (DFs) of asymptomatic unerupted third molars is not entirely clear. The aim of this study is to analyze and compare the presence of iNOS immunoreactivity (iNOS-IR) in periapical granulomas (PGs) and radicular cysts (RCs), which are two different stages of PILs in chronic inflammatory process, and in DFs which may transform into chronic inflammatory tissues, cysts and other pathologies. In this study, immunohistochemical method was performed for evaluation of PGs (n=20), RCs (n=33) and DFs (n=24) groups from formalin-fixed, paraffin-embedded sections, in terms of iNOS-IR. The statistical analyses showed that there were no significant differences between PGs, RCs and DFs groups regarding iNOS-IR (p>0.05). The results of this study suggest that the extraction of asymptomatic impacted third molars with DFs is necessary for prophylactic purpose.