Objectives: To investigate if the onset of primary herpetic gingivostomatitis (PHG) is shifting toward an adult age and compare the clinical characteristics of PHG between children and adults. Method and Materials: The charts of patients diagnosed with PHG in an oral medicine clinic in Bucharest, Romania, over a 10-year period were revisited. Diagnosis was based on history, clinical data, and laboratory confirmation (Tzanck cytology, polymerase chain reaction [PCR], or immunofluorescence). Seventy-three cases (38 females, 35 males) were included. The age range was between 22 months and 53 years, with a mean age of 18.6 years. All patients were healthy with no suspicion of HIV infection or immunodeficiency. Results: Nearly 48% (47.94%) of the sample were in the young adult group. General symptoms (fever, malaise, and lymphadenopathy) were equally present in children and adults. The most involved areas were the gingiva, vermilion border, and tongue. No differences in the extent of lesions were observed between children and adults. Inflammatory gingivitis and pharyngotonsillitis were more frequent in children than in adults although their frequency was less than expected. Conclusions: PHG was more frequently observed in young adults than in children. No significant differences between children and adults in the severity of infection were observed. Most of the patients presented widespread lesions. Keywords: gingivostomatitis, oral mucosa, primary herpes