Elevated total serum homocysteine (tHcy) may be a possible risk factor for CVD. A 5 micromol/l increase in tHcy is associated with an approximately 70 % increase in relative risk of CVD in adults. Data for children and adolescents are, however, limited. The purpose of the present study was to provide a reference range for tHcy and investigate any relationship between tHcy and nutritional indexes in a Greek paediatric population. tHcy, folate, vitamin B12 levels and dietary indexes were measured in 520 healthy schoolchildren (274 boys, 246 girls) aged 6-15 years. As in adults, the tHcy distribution skewed to the right, with a geometric mean for both genders of 7.4 (range 3.4-29 micromol/l). Concentrations were lower in young children and increased with age. No statistically significant difference in tHcy level was observed between gender. The 95th percentiles for the three age groups were as follows: 6-9 years, 9.98 micromol/l; 10-12 years, 10.62 micromol/l; 13-15 years, 14.4 micromol/l. Using Pearson's coefficient analysis, tHcy level was correlated with age, serum folate, BMI and systolic blood pressure. Dietary analysis showed that folate, vitamin B12 and fibre intake were inversely related with tHcy; conversely, sugar and fat were positively associated with tHcy. However, in multiple linear regression analysis, only age (odds ratio 0.246, P < 0.05) and folate (odds ratio -0.346, P < 0.05) were significantly and independently associated with tHcy. This study provides age-specific reference data regarding tHcy concentration in a Greek paediatric population. tHcy levels increased as a function of age. Serum folate levels were significantly and independently associated with tHcy levels.