Since 2001, antiretroviral therapy (ART) has been available for people living with HIV (PLHIV) in Lao People's Democratic Republic (PDR). Over 10 years of the ART program many HIV patients were found with advanced-stage AIDS in health care service facilities. This study aimed to examine factors associated with delayed access to ART among PLHIV in the capital of Vientiane. A cross-sectional study was conducted with 283 respondents (131 males and 152 females) aged 15 years or over. In this study, delayed access to ART was defined by a CD4 cell count of less than 350 cells/mm3 at the first screening, or those who presented with advanced AIDS-related symptoms. The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated by a logistic model. After adjustment, young people (OR=2.17; 95% CI: 1.00-4.68; p=0.049), low education (OR=0.23; 95% CI: 0.10-0.55; p=0.001) and duration between risk behavior and HIV test (OR=3.83; 95% CI: 1.22-12.00; p=0.021) were significantly associated with delayed access to ART. Low perception of high risk behaviors was one of the obstacles leading to delayed testing and inability to access ART. Almost all reported feeling self-stigma, and only 30.5% of men and 23.7% of women disclosed the HIV status to his/her partner/spouse. In conclusion, delayed access to ART was associated with individual factors and exposure to health care facility. In order to improve early detection HIV infection following access to ART, an improvement in perceptional knowledge of HIV, as well as reduction of HIV/AIDS-related stigma, might be needed.