This report describes the safety observations following administration of a polyvalent DNA prime-protein boost HIV-1 vaccine formulated with adjuvant QS21. Local injection site reactions were the most common (65% of subjects), and included type IV delayed-type hypersensitivity (DTH) reactions at prior DNA inoculation sites in 12 of 28 (43%) subjects following protein vaccination. Systemic reactions revealed two cases of vasculitis temporally related to inoculation with recombinant Env protein+QS21 adjuvant. Questions remain regarding the cause of the vasculitis, but the unique DTH observation may have contributed to the high level of immune responses previously reported for this vaccine.