Cellular and humoral immunity was examined in 32 children infected with human immunodeficiency virus, living in the Kalmyk ASSR. For comparison purposes, examinations were also made of 6 healthy children and 11 children afflicted with different diseases, living in the same republic. A dramatic lowering of the absolute content of T helper lymphocytes, an appreciable decrease of the T helper/T suppressor ratio associated with the high level of circulating immune complexes were revealed. In children infected with human immunodeficiency virus, grave immunodepression occurred at the early stages of the pathological process. The authors describe the totality of alterations in the immunological parameters, which may give rise to the generalized forms of opportunistic diseases in children infected with human immunodeficiency virus.