Objective: To evaluate the effect of radiant warmers on skin barrier function in preterm infants. Methodology: Transepidermal water loss (TEWL) and stratum corneum hydration were measured in 30 preterm infants (birth weight 825 to 2220 g) in seven body areas: forehead, upper back, cubital fossa, palms, soles. abdomen, and inguinal region. Measurements were performed under radiant warmer and incubator conditions. Each patient served as his/her control. Results: TEWL was significantly higher in the radiant warmer compared to the incubator condition in only two areas: forehead and back. The overall mean difference in percentage TEWL between the conditions Stratum corneum hydration was not affected by the radiant warmer. Conclusions: The use of radiant warmers does not significantly decrease barrier function in the preterm infant.