To determine follow-up rates for the high-risk infant follow-up (HRIF) visit at 18-36months among infants with very low birthweights and identify factors associated with completion. We completed a retrospective cohort study using linked California Perinatal Quality of Care Collaborative neonatal intensive care unit, California Perinatal Quality of Care Collaborative California Children's Services HRIF, and Vital Statistics Birth Cohort databases. We identified maternal, sociodemographic, neonatal, clinical, and HRIF program level factors associated with the 18- to 36-month follow-up using multivariable Poisson regression. From 2010 to 2015, among 19 284 infants with very low birthweight expected to attend at least 1 visit at 18-36months, 10 249 (53%) attended. On multivariable analysis, factors independently associated with attendance at an 18- to 36-month visit included estimated gestational age (relative risk [RR], 1.21; 95% CI, 1.15-1.26; <26weeks vs ≥31weeks), maternal education (RR, 1.09; 95% CI, 1.06-1.12; college degree or more vs high school), distance from clinic (RR, 0.92; 95% CI, 0.89-0.97; fourth quartile vs first quartile), and Black non-Hispanic race vs White race (RR, 0.88; 95% CI, 0.84-0.92). However, completion of an initial HRIF visit within the first 12months was the factor most strongly associated with completion of an 18- to 36-month visit (RR, 6.47; 95% CI, 5.91-7.08). In a California very low birthweight cohort, maternal education, race, and distance from the clinic were associated with sustained HRIF participation, but attendance at a visit by 12months was the most significantly associated factor. These findings highlight the importance of early engagement with all families to ensure equitable follow-through for children born preterm.