Socioeconomic costs of HIV and TB and the difficulty of maintaining optimal treatment are well documented. Social protection measures such as food assistance may be required to offset some of the treatment related costs as well as to ensure food security and maintain good health of the affected individual and household. Programmes have started placing greater emphasis on treatment adherence and are looking for proven interventions that can optimize it. This paper looks at the effect of food assistance for enabling treatment adherence and reviews studies that used food assistance to promote adherence. Eight of ten studies found that provision of food can improve adherence and/or treatment completion for HIV care and treatment, ART and TB-DOTS. This indicates that food provision is not only a biological, but also a behavioural intervention, and underscores that unresolved food insecurity can be an impediment to treatment adherence and consequently to good treatment outcomes.