OBJECTIVE To determine whether serum homocysteine and folate levels are correlated with the occurrence of neonatal asphyxia and to study the effects of gender and gestational age on serum homocysteine and folate levels. METHODS Thirty-five neonates with mild asphyxia (19 males and 16 females) and 40 normal neonates (control group,18 males and 22 females) were enrolled in this study. The asphyxia and the control groups consisted of 10 and 11 cases of preterm infants respectively. Serum homocysteine levels were measured using ELASA. Serum folate levels were measured using radioimmunity assay. RESULTS Serum homocysteine level (14.66+/-2.61 micromol/L vs 7.55+/-0.50 mumol/L; P<0.05) was significantly higher and serum folate level (2.47+/-0.24 ng/mL vs 3.28+/-0.28 ng/mL; P<0.05) was significantly lower in the asphyxia group than that in the control group. There were no significant differences in serum levels of homocysteine and folate between males and females either in the asphyxia group or the control group. The asphyxiated neonates born at premature showed increased serum homocysteine level compared with the full-term neonates with asphyxia (21.25+/-5.01 micromol/L vs 12.34+/-2. 01 micromol/L; P<0.05). CONCLUSIONS The increased serum homocysteine level and decreased serum folate level are correlated with the occurrence of neonatal asphyxia. Serum homocysteine and folate levels are not associated with the gender. A more significantly increased serum homocysteine level may be found in asphyxiated neonates born at premature.