DNA samples from lymphocytes of 11 AIDS patients were used for amplification of HTLV-I GAG, HTLV-II POL and HIV GAG and POL gene sequences. The primer pairs used were GP1/GP2 for HTLV-I GAG, SK110/SK111 for HTLV-II POL, SK38/SK39 for HIV GAG and SK32/Sk33 for HIV POL. The oligoprobes for hybridization were GP3 for HTLV-I GAG, SK188 for HTLV-II POL, SK19 for HIV GAG and SK34 for HIV POL. 3/11 DNA samples were positive for HIV GAG and 2/11 for HIV POL. HTLV-L or HTLV-II gene sequences were not detected in any of the DNA samples form AIDS patients. Additionally, lymphocytes from four AIDS patients were co-cultured on purified macrophages and maintained for four weeks. The cells from co-cultures were harvested on week 1, 2, 3 and 4 and DNA extracted. The DNA samples were amplified for HTLV-I GAG, HTLV-II POL and HIV GAG and POL gene sequences. HTLV-I or HTLV-II gene sequences were not detected in any of the four cultures. HIV GAG and POL gene sequences were detected in all 4 cultures. Virus from one culture was grown and passaged. The DNA from this culture was digested with restriction enzymes, EcoRI, BamHI, PstI, BamHI/PstI and SSTI and Southern blotted. The Southern blot was hybridized with a full length HIV probe. The results showed the presence of a complete HIV genome in this DNA.