Objective: The main objective of this study was to investigate the frequency of oral manifestations in children with acquired immunodeficiency syndrome. It also attempted to correlate the presence of lesions with the patient's degree of immunosuppression, as measured by the T4/T8 ratio. Method and materials: Oral examinations were performed in 51 children with acquired immunodeficiency syndrome for a 2-year period. A questionnaire used in this investigation was based on the children's classification proposed by the Centers for Disease Control in 1987. The children's T4/T8 ratios were obtained from their medical files. Results: Pseudomembranous candidiasis was the most common lesion, found in 21.57% of the children. Salivary gland disease was present in 19.61% of patients. Erythematous candidiasis was observed in 5.88%, and linear gingival erythema and oral hairy leukoplakia were both observed in 1.96% of children. Children with a T4/T8 ratio 0.5 were more prone to development of pseudomembranous candidiasis. Conclusion: Pseudomembranous candidiasis was the most common type of oral lesion in human immunodeficiency virus-positive children with acquired immunodeficiency syndrome. There was a relationship between the frequency of oral manifestations and the patient's T4/T8 ratio.