The nested polymerase chain reaction (PCR) assay was used to determine the sequences of reverse transcriptase (RT) codons 41, 67, 70, 210, 215 and 219 of human immunodeficiency virus-1 (HIV-1) pol gene. Template DNA was obtained from uncultured peripheral blood mononuclear cells from 27 Korean HIV-1 infected patients treated with ZDV and Korean red ginseng. The second PCRs were done for 2 separated regions (RT codons $13{sim}98$ and $152{sim}259$) with $5;{mu}l$ of the first PCR productNucleotide sequences were determined by direct sequencing. In the 27 patients, CD4+ cell count decreased from $230{pm}117/{mu}l$ to $152{pm}162/{mu}l$ for $46{pm}26$ months (Mo), and actual duration of ZDV intake was $72{pm}16$ Mo. In the 16 patients who had been treated with ZDV therapy ${ge}25$ Mo, the incidences of 70R, 215F/Y, and 41L were 61%, 28% and 22%, respectively and those of 67N, 210W and 219Q were 17%. The incidences of 215F/Y were 6.7% for group ${le}12$ Mo treatment, 22.7% for group with 13 to 24 Mo, and 27.8% for group ${ge}25$ Mo. There was no mutation in 9 patients. It might be associated with the interruption of ZDV therapy for more than 6 months in 6 patients. This study shows that the detection of mutation could be useful prognostic marker with other clinical and virological data, and very low mutation rate is dectected compared to overseas reports.