We analysed whether mutations associated with resistance to antiretroviral (ARV) drugs circulate among treatment-naive HIV-1-infected individuals at a period when these drugs started to become more widely available in Africa. Overall, major resistance mutations in the pol gene, as defined by the International AIDS Society Resistance Testing-USA panel, were observed in 16 treatment-naive individuals. Eight of the 97 patients tested in Burkina Faso bore mutations conferring resistance to one drug class of ARV drugs: two to nucleoside reverse transcriptase inhibitors (NRTIs; M41L [ n=1], M41L+T69S [ n=1]), four to non-NRTIs (NNRTIs; V106A/V [ n=1] and V108I [ n=3]) and two to protease inhibitors (PIs; L33F [ n=2]). In Cameroon, resistance mutations were identified in 8 of 102 patients: three to PIs (M46I/L [ n=2], L33F [ n=1]), three to NRTIs (T69N/T [ n=1], M184V [ n=1], A62V [ n=1]) and two to NNRTIs (P236L [ n=1], V108I [ n=1]). It is important to note that not all geno-typic drug-resistance algorithms give similar interpretations to the observed mutations. Population surveillance for ARV drug resistance is required and should be included in all implementation programmes.