Glycated haemoglobin (HbA(1c)) is considered the best index of glycaemic control in established diabetes. It may also be useful in the diagnosis of diabetes and as a screening tool. Little is known about the distribution of HbA(1c) in healthy children and its predictors. The aim of this study is to describe the distribution of HbA(1c) in non-diabetic Dutch children aged 8-9 years and to investigate potential associations of HbA(1c) in this group. HbA(1c) was measured in 788 non-diabetic children aged 8-9 years participating in the PIAMA birth cohort study. Data on parents and children were collected prospectively by questionnaires. Weight, height and waist and hip circumference of the children were measured when blood samples were taken. Mean (sd) HbA(1c) was 4.9 +/- 0.33%, range 3.5-6.0%. HbA(1c) was significantly higher in boys (4.9 +/- 0.31 vs. 4.9 +/- 0.33%) and in children of mothers with gestational diabetes (5.0 +/- 0.37 vs. 4.9 +/- 0.32%). We found a significant inverse association between HbA(1c) and haemoglobin (regression coefficient: -0.169 (95% CI -0.221 to -0.118), P <0.001). HbA(1c) was not significantly associated with age, body mass index, waist circumference, parental diabetes or maternal body mass index. We found no significant relation between known risk factors for Type 2 diabetes and HbA(1c) at age 8-9 years. Moreover, there was a significant inverse association between haemoglobin and HbA(1c). These results suggest that HbA(1c) may not only reflect the preceding blood glucose levels, but seems to be determined by other factors as well. Diabet. Med. 26, 122-127 (2009).