Antiretroviral therapy (ART) has transformed HIV infection into a treatable, chronic condition. However, the need to continue treatment for decades rather than years, calls for a long-term perspective of ART. Adherence to the regimen is essential for successful treatment and sustained viral control. Studies have indicated that at least 95% adherence to ART regimens is optimal. It has been demonstrated that a 10% higher level of adherence results in a 21% reduction in disease progression. The various factors affecting success of ART are social aspects like motivation to begin therapy, ability to adhere to therapy, lifestyle pattern, financial support, family support, pros and cons of starting therapy and pharmacological aspects like tolerability of the regimen, availability of the drugs. Also, the regimen's pill burden, dosing frequency, food requirements, convenience, toxicity and drug interaction profile compared with other regimens are to be considered before starting ART. The lack of trust between clinician and patient, active drug and alcohol use, active mental illness (e.g. depression), lack of patient education and inability of patients to identify their medications, lack of reliable access to primary medical care or medication are considered to be predictors of inadequate adherence. Interventions at various levels, viz. patient level, medication level, healthcare level and community level, boost adherence and overall outcome of ART.