AbstractNew models for determining the cost of care and length of stay in the neonatal intensive care unit (NICU) were developed using financial and clinical data from 588 admissions to our NICU. The model for determining costs explained 71% of the variability in total hospital costs. Models such as the ones developed in this study can be used to compare costs in different institutions, determine temporal trends in costs, and examine the financial impact of using new technologies. Such models can also be useful components of a rational prospective pricing system for the NICU.