The 32-nucleotide deletion (delta 32) within the chemokine co-receptor CCR5 gene was studied in 1,031 DNA samples from various racial origins. The mutation is absent in 48 Vietnamese living in Paris, and we confirm that delta 32 allele is very rare in a sample of 302 individuals originating from sub-Saharan Africa. The mean delta 32 allelic frequency in unrelated non-HIV-1 infected blood donors is 0.113 in France, as calculated in a sample of 620 individuals. A slight decrease in allelic frequencies was noticed in the southern part of the country compared to the Paris region. In a population of 71 North African people the delta 32 frequency is 0.063, a value significantly lower than the mean frequency observed in France.