The era of genomic medicine, anticipated since the completion of the Human Genome Project in 2003, is now upon us. Before long, genomic information will be an integral part of the medical record, and paediatricians will be able to interrogate these data for a range of purposes: to make a diagnosis in a sick child, to diagnose or exclude a rare genetic disorder, to identify and anticipate future health problems, or to increase the precision of medication prescribing. At the heart of genomic medicine is the use of genomic data, derived from the whole human genome, to better diagnose, predict and treat disease. The availability of clinical-level sequencing and analysis of the whole genome is predicted to transform many aspects of paediatric medicine over the next 5 years and may ultimately become as routine as serum biochemistry.