We sought to describe neonatal morbidities and therapeutic interventions in very low-birth-weight (VLBW) and extremely low-birth-weight (ELBW) infants cared for in Spanish hospitals. We preformed a prospective collection of data covering the perinatal period until discharge by the SEN1500 network. This network, set up by the Spanish Society of Neonatology, targets VLBW and ELBW infants (400 to 1500 g) admitted to neonatal units in Spanish hospitals. Data were recorded in electronic form and controlled for possible errors or inconsistencies before analysis. We report data for 8836 neonates admitted to 48 neonatal units from January 2002 to December 2005. Prenatal steroids were given to significantly more newborns in 2003 to 2005 (79.4%) than in 2002 (73.4%), although the remaining perinatal data examined failed to significantly vary. Delivery was by cesarean section in 69.8% of cases but significantly lower (35.9%) for infants under a postmenstrual age of 26 weeks. Hyaline membrane disease was diagnosed in 53.9% of the newborns and bronchopulmonary dysplasia (BPD) in 10.46%. Mechanical ventilation was employed in 69.1%, surfactant in 50.3%, and steroids for BPD in 5.3%. Intraventricular hemorrhage grades 3 to 4 (8.1%) and cystic leukomalacia (2.6%) were the most relevant brain ultrasonography findings. Rates of early- and late-onset septicemia were 5% and 29.4%, respectively. Further diagnoses were necrotizing enterocolitis (NEC; 6.9%) and persistent ductus arteriosus (PDA; 24.2%); 40.6% of the cases of NEC and 15.3% of those of PDA required surgery. In addition, 26.6% of the newborns required supplementary oxygen at 28 days of life. The number of newborns who had not recovered their birth weight at this age fell from 3.1% in 2002 to 1.5% in 2005. Rates of prenatal steroid use, cesarean delivery, and main morbidities were comparable to figures cited for other patient series, although our BPD rate was among the lowest reported and nosocomial sepsis rate among the highest.