BACKGROUND: Kangaroo care (KC) is an evidence-based best practice that can prevent major health complications in preterm infants. However, there is a lack of evidence on the feasibility and safety of placing extremely preterm infants under 28 weeks gestational age in KC position. AIM: To compare thermal stability 60 min after the first KC session in the lateral versus prone position in extremely preterm infants under 28 weeks gestational age. STUDY DESIGN: This is a single-centre, randomized, non-inferiority, parallel clinical trial. The patients were extremely preterm infants during their first 5 days of life. Infants in the intervention group received KC in the lateral position while those in the control group received KC in the prone position. All infants receiving KC were inside their polyethylene bags but maintained skin-to-skin contact. The primary outcome was the axillary temperature of the infants, and the secondary outcome was the development of intraventricular haemorrhage. RESULTS: Seventy infants were randomized (35 per group). The mean gestational age was 26 CONCLUSIONS: The lateral KC position is an alternative to the conventional prone KC position and maintains normothermia in infants under 28 weeks gestational age. RELEVANCE TO CLINICAL PRACTICE: Extremely preterm infants are candidates for KC. Lateral KC position is an evidence-based best practice that can be applied to preterm infants under 28 weeks GA. This evidence is particularly useful in performing umbilical catheterization on these patients.