WHO recommends that pre-exposure prophylaxis (PrEP) be offered as an additional prevention choice for HIV-negative individuals at substantial risk of HIV infection as part of combination prevention approaches. HIV drug resistance has been rarely reported among PrEP users who tested HIV positive in randomized controlled trials or open-label studies. However, PrEP-selected HIV drug resistance could potentially negatively impact the effectiveness of treatment options among PrEP users who acquire HIV, since there is a potential for overlapping resistance profiles between antiretroviral drugs used for both PrEP and first-line antiretroviral therapy.