We compared neonatal characteristics and adverse outcome rates of neonates with hypoxic-ischemic encephalopathy following (1) prolonged partial asphyxia, (2) acute near-total intrapartum asphyxia, and (3) the two combined. The time course of the insult was determined individually by two authors from obstetric data and neonatal charts. “Severe adverse outcome” was defined as death or severe disability detectable by age 2 years. The asphyxial time course was prolonged partial asphyxia in 167 (45%), acute near-total asphyxia in 96 (26%), combined in 78 (21%), and indeterminate in 34 (8%) patients. Among patients with known time course and outcomes, 212 (67%) had severe adverse outcome and 103 (33%) were free of severe adverse outcome. Severe adverse outcome rates were 61% for prolonged partial asphyxia, 67% for acute near-total asphyxia, and 79% for combined time course asphyxia (p = 0.025). Long-term outcomes differ according to the time course of the insult; infants with combined time course had the worst outcome.