Social, behavioural and economic drivers of inappropriate antibiotic use by informal private healthcare providers in rural India. Antibiotics play a life-saving role in reducing mortality and morbidity due to communicable diseases like tuberculosis, typhoid, pneumonia and gastroenteritis. However, the overuse of antibiotics in populations can lead to the disease causing bacteria becoming drug resistant over time. For example, high levels of resistance have been found in gastroenteritis causing bacteria to antibiotics like ampicillin (52.3% - 84.6%), cotrimoxazole (45.5% - 65%), and cephalexin (15.9% - 59.7%) across five sites in India and South Africa. This antimicrobial resistance (AMR) is a global threat because it can reverse the advances made in combating life threatening infections and increase the costs of treatment and hospital stays for the sick, making newer antibiotics even more inaccessible to the poorest and most vulnerable.   One major reason for the overuse of antibiotics in humans is antibiotic over-dispensing and over-prescribing by health care providers. This is a big challenge in low and middle income countries where health systems are weak, regulatory frameworks for health workers and the pharmaceutical industry either do not exist or are weakly enforced, and the majority of poor and rural populations rely on informally trained and unlicenced providers who use antibiotics excessively and inappropriately in their treatments. These informal providers or IPs may constitute from 50% to 96% of all providers in LMICs, including in India, but there is very little in-depth knowledge of the factors that influence their inappropriate antibiotic use and what interventions can feasibly and effectively arrest this inappropriate use. Evidence from the formal sector suggests that antibiotic use is influenced by socio-cultural, behavioural and economic factors. However the precise nature of these factors and how they interact has not been explored in the case of IPs.  In this field study we propose to study a cross section of IPs, and the drivers of their antibiotic use in the state of West Bengal in India. Since IPs lack a clear legal status, few government programmes are willing to engage with them, but the West Bengal government has decided to train and harness more than 100,000 IPs as village health workers, from early 2016. We are therefore locating this timely study in West Bengal. We will explore provider related factors and also the perceptions of communities and various government stakeholders. This will be done through 200 structured and 30 in-depth interviews and observations of IP practices in two socio-economically different districts (Birbhum and South24 Parganas), accompanied by focus groups discussions with community members and key informant interviews with government, pharmaceutical and formal medical sector stakeholders. We will use these findings to conceptualise interventions to reduce antibiotic use among IPs and seek feedback from study participants on the feasibility and effectiveness of these interventions.   The study will be implemented by the London School of Hygiene and Tropical Medicine in collaboration with the Liver Foundation, a non-governmental organisation in West Bengal that has worked with IPs since 2007 and has championed the harnessing of IPs with the state government.  We will use the final study outcomes to develop a proposal with the state government to implement and evaluate these interventions in the future, possibly starting in mid to late 2017. The Global Challenges Research Fund (GCRF) supports cutting-edge research to address challenges faced by developing countries. The fund addresses the UN sustainable development goals. It aims to maximise the impact of research and innovation to improve lives and opportunity in the developing world.