PURPOSE OF REVIEW: Adherence to combination antiretroviral therapy (cART) is one of the most important contributing factors to positive clinical outcomes in patients with HIV, and long-term retention of patients in low-income and middle-income countries is emerging as an important issue in rapidly expanding cART programs. This review presents recent developments in both treatment adherence and retention of patients in low-income and middle-income countries. RECENT FINDINGS: Adherence is among the most modifiable variables in treatment, but there still is no 'gold standard' measurement. Best estimates demonstrate that adherence in resource-limited settings is equal or superior to that in resource-rich settings, possibly due to focused efforts on support groups and community acceptance of adherence behaviors. However, long-term data show that sustained efforts to ensure high cART adherence and evidence of intervention effects are critical, but that resource-intensive interventions are not warranted in settings where cART adherence is high. Furthermore, well conducted evaluation of culturally sensitive interventions to maximize pre-cART and post-cART initiation retention is badly needed in low-income and middle-income settings. SUMMARY: Further research is needed to identify risk factors and to improve adherence and retention among children, adolescents, and adults through use of social networks or emerging technologies for patients at risk for poor adherence.