Asian people are under-represented in population-based, clinical, and genomic research. To address this gap, we have initiated the HELIOS longitudinal cohort study, comprising comprehensive behavioural, phenotypic, and genomic measurements from 10,004 Asian men and women of Chinese, Indian or Malay background. Phenotyping has been carried out using validated approaches, that are internationally interoperable. Health record linkage enriches both baseline phenotyping and evaluation of prospective outcomes. The integrated multi-omics data include whole-genome and RNA sequencing, quantification of DNA methylation, and metabolomic profiling. Our data reveal extensive lifestyle, physiological, genomic, and molecular diversity between the distinct Asian ethnic groups, and the biological interconnectivity between functional layers. This includes characterisation of divergent patterns of genome regulation between Asian individuals, that correlate with differences in educational attainment, dietary quality, and adiposity, and which overlap transcription factors and DNA methylation sites linked to the development of diabetes and other chronic diseases. Our unique HELIOS Asian Precision Medicine cohort study represents a state-of-the art platform to enable biomedical researchers to understand the aetiology and pathogenesis of diverse disease outcomes in Asia, and to generate insights that have the potential to improve health outcomes for Asian populations globally.