This study reports a lentiviral gene transfer protocol for efficient transduction of adult human peripheral blood (PB)-derived CD34+ NOD/SCID-repopulating cells (SRCs) using vesicular stomatitis virus-G protein (VSV-G)-pseudotyped lentiviruses encoding for enhanced green fluorescence protein (eGFP). Lentiviral stocks were concentrated by anion exchange chromatography, and transduction was performed under serum-free conditions at a multiplicity of infection (MOI) between 3 and 50. Similar transduction efficiencies were achieved in the presence and absence of cytokines. Transduction of PB-derived CD34+ cells at a MOI of 3 resulted in gene transfer efficiencies into SRCs of 9.2% and 12.0% in the absence and presence of cytokines, respectively. Using improved lentiviral vectors, transduction frequency varied between 42.0% (MOI 10) and 36.0% (MOI 50) with multilineage transgene expression within SRC-derived myeloid and lymphoid cells. The protocol described can be adapted for clinical application of lentiviral gene transfer into PB-derived CD34+ cells from adult patients.