Objectives: Our primary objective was to determine the incidence of hospital admission and emergency department presentation in Indigenous and non- Indigenous preterm infants aged postdischarge from birth admission to 11 months in Western Australia. Secondary objectives were to assess incidence in the poorest infants from remote areas and to determine the primary causes of hospital usage in preterm infants. Design: Prospective population-based linked data set. Setting and participants: All preterm babies born in Western Australia during 2010 and 2011. Main outcome measures: All-cause hospitalisations and emergency department presentations. Results: There were 6.9% (4211/61 254) preterm infants, 13.1% (433/3311) Indigenous preterm infants and 6.5% (3778/57 943) non-Indigenous preterm infants born in Western Australia. Indigenous preterm infants had a higher incidence of hospital admission (adjusted incident rate ratio (aIRR) 1.24, 95% CI 1.08 to 1.42) and emergency department presentation (aIRR 1.71, 95% CI 1.44 to 2.02) compared with non-Indigenous preterm infants. The most disadvantaged preterm infants (7.8/1000 person days) had a greater incidence of emergency presentation compared with the most advantaged infants (3.1/1000 person days) (aIRR 1.61, 95% CI 1.30 to 2.00). The most remote preterm infants (7.8/1000 person days) had a greater incidence of emergency presentation compared with the least remote preterm infants (3.0/1000 person days; aIRR 1.82, 95% CI 1.49 to 2.22). Conclusions: In Western Australia, preterm infants have high hospital usage in their first year of life. Infants living in disadvantaged areas, remote area infants and Indigenous infants are at increased risk. Our data highlight the need for improved postdischarge care for preterm infants.