Objective: Parents of preterm infants require information on morbidity and duration of common interventions performed in the NICU. Since locally achieved data are often not available, information is mainly based on educated guesses of health care professionals. The present study compares estimates of neonatal nurses or medical doctors (MDs) in two separate NICUs with local data. Methods: Health care professionals were asked to estimate morbidity and duration of medical interventions of two groups of very low birth weight infants. For comparison, local data were obtained from infant charts and the Vermont Oxford Neonatal Network data base. Results: Incidence of BPD was underestimated by MDs and overestimated by nurses for low birth weight group (500-750 g) and overestimated by nurses for 1250- 1500 g infants. Incidence of IVH was significantly overestimated by nurses for both groups. Duration of ventilatory support was underestimated for infants of a gestational age of 24-27 weeks and overestimated for the age group of 31-32 weeks. Length of stay in NICU was underestimated for infants at gestational age of 24-27 weeks, but not for the 32-33 weeks group. Conclusions: Information based on estimates made by health care professionals may be misleading. Data differ significantly among different NICUs, thus, local data should be obtained by each NICU and used to inform parents appropriately.