Anti-Aspergillus fumigatus antibodies (IgG and IgE class) and serum levels of cytokines (gamma Interferon, Interleukin-2 and tumour necrosis factor-alpha) were studied in multitransfused (MT) children in relation to human immunodeficiency virus (HIV) infection. The specific antibodies to Aspergillus fumigatus were present in 25 per cent of MT children seropositive for HIV as compared to only 2 per cent among HIV-negative MT children (X2 = 14, P < 0.001). Estimation of serum cytokines level in MT children showed that the asymptomatic HIV-infected children had elevated levels of gamma interferon (Y-IFN) and tumor necrosis factor-alpha (TNF-alpha) without any alteration of Interleukin-2 (IL-2) level, compared to HIV-negative group. However, clinically diagnosed cases of AIDS in the HIV-infected group showed elevation of all the three cytokines levels as compared to HIV negative group, as well as asymptomatic HIV infected group. Presence or absence of concomitant A. fumigatus infection did not lead to alteration of Y-IFN and IL-2 level in the HIV infected group, while TNF-alpha levels were markedly raised in the cases with evidences of presence of A. fumigatus specific antibodies irrespective of whether the group belonged to asymptomatic HIV infection or clinically proven cases of AIDS. The significance of these altered cytokines profile with respect to occurence of A. fumigatus infection in HIV-positive MT children has been discussed.