As part of the WHO Network for HIV Isolation and Characterization, we PCR amplified, cloned, and sequenced gp120 and gp160 genes from 12 HIV-1 isolates collected in four WHO-sponsored vaccine evaluation sites (Brazil, Rwanda, Thailand, Uganda). Envelope clones were derived from PBMC-grown isolates obtained from asymptomatic individuals within 2 years of seroconversion. Analysis of their deduced amino acid sequences identified all but one to contain an uninterrupted open reading frame. Transient expression and biological characterization of selected gp160 constructs identified six clones to encode full length and functional envelope glycoproteins. Phylogenetic analysis of their nucleotide sequences revealed that they represent HIV-1 subtypes A, B, C, and E. Since current knowledge of HIV-1 envelope immunobiology is almost exclusively derived from subtype B viruses, these reagents should facilitate future envelope structure, function and antigenicity studies on a broader spectrum of viruses. This should assist in the design and evaluation of effective vaccines against HIV-1.