Cord blood triglyceride (TG) concentrations were determined in 60 neonates whose parents had normal plasma cholesterol and triglyceride levels, and in 57 neonates with one parent having primary hypertriglyceridemia. The 95th percentile value for cord blood triglyceride in both groups of neonates was 70 mg/100 ml, and this level was arbitrarily used as a cutoff point in the definition of cord blood hypertriglyceridemia. In 2,000 consecutive live births, 56 neonates had cord blood triglyceride levels > 70 mg/100 ml (mean TG 111±33, range 71 to 218 mg/100 ml). Forty-six neonates with triglyceride levels <70 mg/100 ml (mean TG 31, range 1 to 70 mg/100 ml) were selected as controls. Cord blood hypertriglyceridemia was highly associated with maternal-fetal problems, including maternal hypertension, prolonged duration of labor, umbilical cord around the infant's neck, meconium-stained amniotic fluid, postterm delivery, and decreased one-minute Apgar scores. For all neonates studied (102) there was a linear relationship between the number of significant perinatal factors and the cord blood triglyceride level (r = 0.61, P <.001). Hypertriglyceridemia at birth may be a useful indication of intrapartum or antepartum fetal stress or compromise.