The Expanded Programme on Immunization (EPI) was launched in Pakistan in 1978. It aims at protecting children by immunizing them against Childhood Tuberculosis, Poliomyelitis, Diphtheria, Pertussis, Measles, Tetanus and also their mothers against Tetanus. The purpose of EPI is to initiate a collective effort to reduce the mortality results from the seven EPI target diseases by immunizing children of the age 0-11 months and women of child bearing age. Although Pakistan has made impressive gains in increasing the EPI coverage in the recent years, the public awareness and thus pubic support and participation in immunization drives of the Ministry of Health, Government of Pakistan needs to improve further to enable us to achieve the targets set under the Millennium Development Goals (MDGs). The elected representatives of the people in the Parliament and the Provincial Legislatures can play a very important role in enhancing the understanding and participation of their communities in the EPI initiatives. It is however critical that these elected representatives are themselves aware of the significance of EPI, its current status and the challenges being faced in this context. They should also be aware of the progress being made in their constituencies on EPI within the context of the overall national state of immunization. This briefing paper has been specially commissioned by PILDAT to give the background and current status of immunization in Pakistan with an aim to brief Parliamentarians and Provincial Legislators on this important subject. PILDAT endeavors to enhance the awareness of elected legislators to act proactively to urge the Government to address the issues in the immunization programme in Pakistan. This paper has been authored by Dr. Haris Ahmed, a senior Public Health expert with international experience.