The objective of this study was to determine the correlation of the radiographic and morphological features of the dental follicle of unerupted third molars with incomplete root formation. A cross-sectional study was carried out with 56 patients (105 teeth) aged 13 to 24 years. Panoramic radiography was used to determine the stage of root formation to locate and measure pericoronal radiolucency. The width of the dental follicle ranged from 0.0 to 4.0 mm, the distal face being the one most frequently involved, and stage 7 of root formation showing the highest incidence. An inactive enamel reduced epithelium and inactive epithelium remnant also showed a high incidence. Dense connective tissue showed a high incidence, chronic inflammation was infrequent and calcification was a common finding. There was a significant association between the progression of the rhizogenesis and the transformation of the enamel reduced epithelium into a stratified squamous epithelium. No significant association was found between rhizogenesis and the other morphological findings or between the latter and the width of the pericoronal space. It was concluded that there was no clinically significant correlation between the radiographic and morphological features. Every asymptomatic unerupted third molar should be followed up and the follicular tissue analyzed.