3753 Cruithne was discovered on October 10, 1986, by Duncan Waldron on the UK Schmidt Telescope at Siding Spring Observatory, Coonabarabran, Australia. The 1983 appearance is given to Giovanni de Sanctis and Richard M. West of the European Southern Observatory in Chile. It was not until 1997 that its unusual orbit was found by Paul Wiegert and Kimmo Innanen, working at York University in Toronto, and Seppo Mikkola, working at the University of Turku in Finland. The asteroid is named after the Cruithne, a people of early medieval Ireland.