Segariu is a comune (municipality) in the Province of Medio Campidano in the Italian region Sardinia, located about 40 kilometres (25 mi) northwest of Cagliari and about 7 kilometres (4 mi) east of Sanluri. As of 31 December 2004, it had a population of 1,353 and an area of 16.7 square kilometres (6.4 mi2).