Increased levels of unbound Free Fatty acid (FFAu) have been found in adults undergoing coronary angioplasty as a result of acute hypoxia-ischemia. We hypohesized that infants suffering from a 1-minute Apgar score of less than 5 will demonstrate elevated FFAu levels in the cord blood. One hundred ninety-nine infants between 25 and 41 weeks gestational age were enrolled in the study. Infants with an Apgar score of less than 5 at 1 minute served as the study group. Blood samples were collected from the umbilical cord and serum FFAu levels were measured with the fluorescent probe acrylodan-derivatized intestinal fatty acid binding protein. The low Apgar score group (n=32, birthweight 3153+/-780 g, gestational age 37.9+/-3.1 weeks) and normal Apgar score group (n=167, birthweight 3067+/-847 g, gestational age 37.5+/-3.5 weeks) were significantly different with respect to Apgar score at 1 minute (3.0+/-1.2 versus 8.4+/-1.1), Apgar score at 5 minutes (6.9+/-versus 8.9+/-0.5), cord pH (7.16+/-0.12 versus 7.28+/-0.07), and in the frequency of meconium passage (40.6% versus 14.9%). Cord FFAu levels were 4.4+/-1.7 versus 3.2+/-1.2 nM (p<0.001), respectively. Cord FFAu correlated inversely with Apgar score at 1 minute (r=-0.31, p<0.05) and with cord pH (r=-0.12, p<0.05), but not with birthweight or gestational age. In infants with low 1-minute Apgar scores, cord free fatty acid levels were significantly elevated compared with those from controls.