Hyperhomocysteinemia is an independent cardiovascular risk factor that depends on folate and vitamin B12 nutrition. Aim: To measure homocysteine, folic acid and vitamin B12 serum levels in healthy children with and without a family history of cardiovascular disease. Subjects and methods: Forty children aged 6 to 15 years with a family history of cardiovascular disease, and 40 age and sex matched children without such history were studied. Serum homocysteine, folic acid and vitamin B12 were measured in a fasting blood sample. Homocysteine was measured by a fluorescence polarization immunoassay (FPIA), vitamin B12 by enzymatic microparticle assay, covered with intrinsic factor and folic acid by ionic capture, using commercial kits. Results: Children with family history of cardiovascular disease had higher homocysteine levels than their counterparts without family history (7.9±3 and 5.8±2 µmol/l respectively, p <0.03), but similar folic acid (5.2±1.8 and 5.5±1.4 pg/ml respectively) and vitamin B12 levels (431±213 and 445±209 ng/ml respectively). There was a negative and significant correlation between homocysteine and folic acid and vitamin B12 levels. Conclusions: Children with a family history of cardiovascular disease have higher levels of serum homocysteine than those without such history, despite having similar levels of folic acid and vitamin B12