Assembly of normally soluble proteins into amyloid fibrils is a cause or associated symptom of numerous human disorders. Although some progress toward understanding the molecular-level details of fibril structure has been made through in vitro experiments, the insoluble nature of fibrils make them difficult to study experimentally. We describe two computational approaches used to investigate fibril formation and structure: intermediate-resolution discontinuous molecular dynamics simulations and atomistic molecular dynamics simulations. Each method has its strengths and weaknesses, but taken together the two approaches provide a useful molecular-level picture of fibril structure and formation.