Few human immunodeficiency virus (HIV) positive Defence Security Corps (DSC) personnel reported for surveillance at one of the Air Force (AF) stations in 1992 and it was appropriate to study socio-behavioural profile of HIV positive DSC personnel to determine the reason for their vulnerability.The study was conducted among 46 HIV positive DSC personnel during 1992-2004 at various AF stations. Pretested questionnaires were introduced to the subjects to ascertain their demographic, social, educational and behavioural profile vis-à-vis their HIV-AIDS awareness.Majority of the subjects detected during pre-donation screening were middle aged, rural, semiliterate, (56.5%) and acquired the disease through heterosexual (95.66%) mode, mostly from commercial sex workers (CSWs). All were aware of HIV-AIDS prevention and most of them (77.2%) stated that condoms were easily available but 70.7% did not use the same for the fear of failure to perform under the influence of liquor. 74% subjects were found complying with medical instructions.The study brings out a discernable gap between the knowledge and practice of safe sex. Adequate preventive knowledge did not always result in practice of safe sex.