Objective To document catch-up growth in children in the first 18 months after gastrostomy surgery and characterize how weight and length growth differ according to medical and nutritional risks. Design Repeated measures study to evaluate weight and linear growth in gastrostomy-fed children. Subjects/setting Seventy-five subjects met the selection criteria: gastrostomy placement anytime from birth to age 6.5 years, diagnosis of failure to thrive before gastrostomy surgery, absence of nonmedical barriers to adequate nutrition. Children were seen in specialty outpatient clinics. Outcome measures Three measurements of weight and length: at the time of surgery and 12 and 18 months after surgery. Statistical analyses Paired t tests of z scores were used to determine catch-up growth. Analysis of variance used variables (age of placement, ambulatory status, prematurity, mode of feeding) to determine statistically significant predictors of growth. Results After gastrostomy surgery, catch-up growth was observed in height and weight for children regardless of prematurity or age at the time of gastrostomy placement. Ambulatory children did not achieve catch-up growth, but nonambulatory children did. At 18 months after surgery, catch-up growth occurred in children whose sole source of nutrition was through the gastrostomy, as well as in those who were able to receive nutrition by mouth. Children with a diagnosis of cerebral palsy experienced better growth than children with other diagnoses. Conclusion/application Failure to thrive in children up to age 6.5 years can be corrected when adequate nutrition is provided. Benefits of gastrostomy surgery observed in catch-up growth reinforce the importance of medical nutrition therapy.