WHO-ERS Train the Trainer (TTT) in smoking Cessation (SC) is a successive 3year collaboration (2016- 19) to support WHO’s training activities for building capacity of WHO Member States to provide SC interventions (SCIs) to smokers both in hospital and primary care settings. 5 countries with high prevalence of tobacco use and low availability of SC support were selected (Greece, Moldova, Bangladesh, Ecuador, Nigeria). 1) A national training network capable of further training HCPs was established to provide brief TCIs to respiratory patients, 2) an online 6module training course on brief TCIs for HCPs was developed in English. The TTT workshops were jointly conducted by WHO and ERS experts as 30 HCPs were trained on brief SCIs in each country and subsequently endorsed to train others through structured cascading training programs. Consequently, the national training teams conducted 4-6 training workshops for primary care providers (PCP) from 2-4 cities in each country. All trained PCPs were supported to deliver 5As and 5Rs brief SCIs. More than 12.000 smokers were enrolled and given brief advice on quitting as existing training centres for on-the-job training of PCPs was strengthened in all countries to train PCPs on brief TCIs. Success quitting rates at 1m. were (37.1%, 31.7%, 48.4%and 60% respectively) although from unexperienced HCPs. We stress the example of Ecuador where quitting rates at 4 months was 57.2% and at 6 m. 48.9%. The WHO–ERS SC TTT is a concrete example of how international cooperation is essential for building capacity of WHO Member States’ health systems to promote one of the wide-reach approaches to SC: brief SCIs as part of HCPs’ routine practice.