Developmental positioning for preterm infants is an essential skill for neonatal intensive care unit (NICU) nurses. The benefits of developmental positioning are evident in the literature, but less is known about how NICU nurses learn about developmental positioning. This study examined the effect of the Infant Position Assessment Tool (IPAT) and informal education on the developmental positioning skills of NICU nurses. This quasi-experimental study measured IPAT scores before and after an educational intervention, and found a statistically significant increase in the means of the two groups. The use of the IPAT and bedside education is useful for improving the developmental positioning proficiency of NCU nurses