A fibrillation-resistant insulin analogue may be a single-chain insulin analogue or a physiologically acceptable salt thereof, containing an insulin A chain sequence or an analogue thereof and an insulin B chain sequence or an analogue thereof connected by a polypeptide of 4-10 amino acids. The fibrillation-resistant insulin analogue preferably displays less than 1 percent fibrillation with incubation at 37° C. for at least 21 days. A single-chain insulin analogue displays greater in vitro insulin receptor binding than normal insulin while displaying less than or equal binding to IGFR than normal insulin. The fibrillation-resistant insulin may be used to treat a patient using an implantable or external insulin pump, due to its greater fibrillation resistance.