Background: Milk curd obstruction as a cause of intestinal obstruction has been known since 1959, but has nearly disappeared. However, in recent years it has experienced a revival in small premature infants. Objective: The aim of this study was to evaluate the clinical characteristics of milk curd obstruction (lactobezoar) in preterm infants. Methods: Data of preterm infants with milk curd obstruction cared for at a large tertiary neonatal intensive care unit between 2012 and 2016 were retrieved from the electronic registry and paper records. Results: A total of 10 infants (2 girls, 8 boys) were identified: the median birth weight was 595 g (range 270-922), gestational age was 24.4 weeks (23.4-27.0), weight-for-gestational age percentile was 16 (0-62), and age at diagnosis was 28 days (16-64). Five infants (50%) were small for gestational age. All neonates had received fortified human milk (added protein 2.0 g/100 mL, range 0-2.8; added calcium 2,400 μmol/100 mL, range 0-6 844; added phosphate 2,400 μmol/100 mL, range 0-5,178). Seven neonates underwent surgery, and 2 infants died. Hyperechoic masses in extended bowel loops, visualised by abdominal ultrasound, and pale/acholic faeces were hallmarks of milk curd obstruction. Conclusions: In this study, milk curd obstruction occurred exclusively in infants with a birth weight < 1,000 g (2.2%) and <28 weeks' gestational age (2.4%). Male and small for gestational age infants appeared to be at increased risk. Paying attention to the colour of the faeces of infants at risk might help to diagnose milk curd obstruction at an early stage.