Abstract Many countries struggle to find the best way to treat hypertension (HT) and type 2 diabetes (T2D). As a result, many patients receive suboptimal care, especially vulnerable groups in society. The SCale up Integrated Care for diaBetes and hYpertension (SCUBY) project addresses this important societal issue, by examining the scale-up of existing evidence-based interventions for the control of HT and/or T2D. The study undertaken in countries with very different health systems, i.e. a developing health system in a low-middle income country - Cambodia; a former socialist high-income country with a centralised health system - Slovenia; and a Western European federal country with a decentralised system- Belgium, develops, implements and assesses roadmaps for the scale-up of an integrated chronic care package (ICP). The ICP consists of (a) identification of people with HT or T2D, (b) subsequent treatment in primary care services, (c) health education, (d) self-management support to patients and caregivers, and (e) collaboration between caregivers. Analysis of the organisational capacity to scale-up the ICP for T2D and HT and to assess contextual barriers and facilitators to do so, informs the development of the roadmaps. Implementation and evaluation of the 3 roadmaps, one per country, assesses the impact on health outcomes and quality of care through the scale-up of the ICP aimed to contribute to sustainable coverage of T2D and HT interventions for more people in each country. The project is innovative because it compares different scale-up strategies for a contextualised common intervention package. It applies the conceptual insights from scale-up science to the field of non-communicable diseases and involves policy-makers, professionals and patients to ensure local relevance and impact. It will generate new knowledge on how to scale-up the ICP for T2D and HT in diverse contexts. The lessons on scale-up will benefit policy-makers in countries with similar contexts. Key messages Innovative strategies are ...