Community health can reduce inequalities in health and improve the health of the most disadvantaged populations. In 2007, Barcelona Salut als Barris (Barcelona Health in the Neighbourhoods) was launched, a community health programme to reduce social inequalities in health. In 2018, this programme reached the 25 most disadvantaged neighbourhoods of the city. This article shares the lessons learned after 12 years of work. The programme was initially funded by a research grant and the funds were maintained during the economic crisis and were tripled when the programme became a political priority in the last municipal government. During the 12-year period, partnerships with stakeholders were generally stable and productive. Maximum community participation was obtained in the detection of health assets and needs and in action plans. During 2018, Barcelona Salut als Barris worked with more than 460 agents that co-produced 183 interventions involving more than 13,600 people. Most of the interventions assessed showed improvements in the health of participants, which could help to reduce health inequalities. The greatest difficulties were: a) citizen participation, b) the sustainability of working groups over the years, c) conflicts of interest, d) the sustainability of interventions, e) reaching certain minority groups and f) evaluation. The increase in resources in the last period contributed to the maturity and expansion of the programme. Key factors in its scope and results were political will, strong technical capacity and methodology, strong intersectoral partnerships and continued community work.