Crohn’s disease and ulcerative colitis are the two most common forms of inflammatory bowel disease (IBD). They are complex diseases characterised by severe gastrointestinal inflammation. Genome-wide association studies (GWAS) have identified hundreds of genetic loci associated with these disease. In this seminar I will present results from the latest GWAS and whole-exome sequencing studies of IBD, which have together identified hundreds of new susceptibility loci. I will also show how we have used single-cell RNA sequencing data from hundreds of samples to robustly identify genes differentially expressed between cases and controls, identify disease-relevant cell-types, map eQTLs at single cell-type resolution and nominate likely disease effector genes in a high-throughput manner. I will finish by describing two large longitudinal multiomic studies we are undertaking to identify biomarkers of drug response and disease progression.