The study refers to children of 0-15 years of age, infected with HIV and who developed a chronic hypertrophic parotitis (CHP), admitted to the "Colentina" Clinic of Infectious Diseases--Paediatrics in Bucharest, between January 1, 1990 and May 15, 1993. Among the total number of 579 HIV infection cases hospitalized in the above-mentioned period, 135 were associated with CHP, hence an incidence of 23.3%. The HIV infection was defined by two ELISA-positive assays, confirmed by a Western-blot test. No specific laboratory test for the diagnosis of CHP in the course of HIV infection was available. The detection of a uni- or bilateral painless parotid enlargement, without signs of skin inflammation in HIV-infected children, was conclusive for the diagnosis of CHP. IgG type anticytomegalovirus antibodies were detected in 41.17% (7/17) and anti-Toxoplasma antibodies in 50% of the tested cases (4/8). The immunogram performed in 85 children showed increased IgG values in 92.94% of cases (79/85) and increased IgM values in 85.88% (73/85). There was recorded a significant increase in the levels of immunoglobulins, especially of IgM, which exceeded 13 times the normal values. The CD8 cells were frequently normal or increased (94.44%, respectively 34/36). CHP appeared before a marked deterioration of CD4 cells, simultaneously with the CD8 cells proliferation. CHP developed at a stage of the HIV infection when the medium-term prognosis was still considered favourable.