Access to medicines is a major challenge for people in developing countries. With the right medicines, diseases such as HIV and AIDS, tuberculosis (TB), and malaria are treatable. Yet for millions of poor people, affordable medicines remain out of reach. UNITAID was established in 2006 as a new public health financing mechanism and a South-North collaboration. It is partially funded through an innovative airline tax that ensures stable long-term financing. UNITAID uses this unique feature to intervene in the market to make medicines for HIV, TB, and malaria affordable and available to people in low- and middle-income countries. Civil society (NGOs and communities affected by the diseases) plays an important role in influencing UNITAID policies and strategies. This document has been produced for the Civil Society Delegations to the UNITAID Board, and aims to encourage more civil society organisations to engage, so that UNITAID benefits from our collective inputs.