We compared short-term neonatal outcomes between premature infants with spontaneous preterm birth (s-PTB) and those delivered due to preeclampsia (PEC). Data were collected from women with singleton pregnancies admitted with spontaneous preterm labor (PTL) (2002 to 2005) and PEC (2005 to 2007). Patients delivering 24 to 36(6/7) weeks were analyzed. The incidence of adverse outcomes was compared. Chi-square and Fisher exact tests compared outcomes between neonates of varying gestational ages, and Poisson regression was used to control for confounders. Data describing 368 infants are included (PTL: n = 224; PEC: n = 144). Overall, s-PTB infants had less favorable outcomes at earlier gestational ages, and at later gestational ages those born preterm secondary to PEC (pec-PTB) had less favorable outcomes. s-PTB infants 24 to 27(6/7) weeks were 21% more likely to stay in the neonatal intensive care unit (NICU) > or = 8 days than pec-PTB infants (incident rate ratios [IRR] 0.79, P = 0.002, 95% confidence interval [CI] 0.68 to 0.92). Pec-PTB infants 32 to 33(6/7) weeks were 6 times more likely to stay in the NICU > or = 31 days than s-PTB infants (IRR 5.82, P = 0.03, 95% CI 1.20 to 28.31). Short-term neonatal outcomes differ by the etiology of preterm birth. These data can help facilitate proper patient counseling and allocation of resources. Future studies should address mechanisms by which the etiology of PTB leads to specific adverse outcomes, thus allowing for more direct interventional strategies.