Closed circular (cc) forms of extrachromosomal HIV DNA are detected in patients with high viral loads; however, it is unclear whether these forms remain if virus replication is suppressed to undetectable levels by combination antiretroviral therapy. A nested primer polymerase chain reaction amplification assay was used to detect the presence of ccDNA containing two long terminal repeat sequences (2-LTR) in PBMC of patients with low or undetectable plasma HIV RNA. Fifty percent of patients with plasma RNA levels <50 copies/ml of blood had detectable 2-LTR DNA. Sequencing of the products identified normal LTR-LTR junctions in the minority of cases with the majority containing anomalies including deletions and insertions. The persistence of HIV ccDNA in patients with no detectable plasma RNA could be consistent with ongoing de novo infection of dividing cells or with stability of this form of DNA in nondividing cells.