To examine resource and service use after discharge among infants born extraordinarily preterm in California who attended high-risk infant follow-up (HRIF) clinic by 12months corrected age. We included infants born 2010-2017 between 22+0/7 and 25+6/7weeks' gestational age in the California Perinatal Quality Care Collaborative and California Perinatal Quality Care Collaborative-California Children's Services HRIF databases. We evaluated rates of hospitalization, surgeries, medications, equipment, medical service and special service use, and referrals. We examined factors associated with receiving ≥ 2 medical services, and ≥ 1 special service. A total of 3941 of 5284 infants received a HRIF visit by 12months corrected age. Infants born at earlier gestational ages used more medications, equipment, medical services, and special services and had higher rates of referral to medical and special services at the first HRIF visit. Infants with major morbidity, surgery, caregiver concerns, and mothers with more years of education had higher odds of receiving ≥ 2 medical services. Infants with Black maternal race, younger maternal age, female sex, and discharge from lower level neonatal intensive care units (NICUs) had lower odds of receiving ≥ 2 medical services. Infants with more educated mothers, multiple gestation, major morbidity, surgery, caregiver concerns, and discharge from lower level NICUs had increased odds of receiving a special service. Infants born extraordinarily preterm have substantial resource use after discharge. High resource utilization was associated with maternal/sociodemographic factors and expected clinical factors. Early functional and service use information is valuable to parents and underscores the need for NICU providers to appropriately prepare and refer families.