Chemokine receptors have recently been shown to mediate HIV-1 entry into cells. The chemokine receptor CCR5 plays a key role in this process. A 32-bp deletion within the coding region of the CCR5 gene generates a truncated nonfunctional receptor. In HIV-1-infected individuals homozygous for this mutation, disease progression is inhibited. We analyzed the frequencies of the deletion in HIV-1-infected seropositive individuals. No significant differences in allelic frequencies of the CCR5 gene between the control and general HIV-1-infected cohorts and within the latter group between the infected individuals and patients with AIDS symptoms were revealed.