Fifteen low birth weight infants had their conditions complicated by the formation of a lactobezoar. The mean gestational age was 30.3 weeks; mean birth weight was 1,184 g, and the mean age at the time of diagnosis was 11.8 days. Twelve of the infants were receiving an 80 kcal/dL-formula and one infant, a 40 kcal/dL-formula designed for the premature infant. Symptoms included abdominal distension, emesis or increased gastric residual, diarrhea, hematest-positive stools, abdominal mass, and gastric perforation.