Objective: To assess the knowledge of and attitudes towards HIV/AIDS among the inmates in Quthing Prison, Lesotho. Method: A semi-structured questionnaire was used to interview the prisoners. Of the 138 prisoners, 123 inmates were successfully interviewed. The data were collated and analyzed quantitatively using the SPSS computer software programme. Results: Ninety-two per cent of the respondents were in the age group 20-44 years, while 57.7% were single and had never married Knowledge about HIV/AIDS was found to be high, as 95.5% of the inmates knew the cause of the disease and over 70% of the inmates knew how it could be transmitted or prevented. A majority of the respondents (68.1%) agreed that people with the disease should be isolated (evidence of unfavourable attitudes); 31.2% believed that there were holes and worms in the condoms (misconception) and 41.5% would not use condom (prevent full sexual enjoyment) despite the risk associated with non-use. Conclusion: Knowledge about HIV/AIDS was found to be high and prisoners had misconceptions about HIV/AIDS and use of condoms.