Background: Ghrelin is a peptide hormone which has been shown to associate with obesity, hypertension and Type 2 diabetes (T2DM) in cross-sectional studies. Aim: To study whether total ghrelin levels have predictive value for the incidence of impaired glucose regulation (IGR) or T2DM. Subjects and methods: The subjects of this prospective follow-up study (no.=201) belonged to a population-based cohort collected in Northern Finland. Oral glucose tolerance tests (OGTT) and measurements of fasting serum total ghrelin, lipids, blood pressure and body mass index were performed at the beginning and at the end of the study. The mean follow-up time was 5.1 yr. The subjects had normal glucose tolerance (NGT) at the beginning of the study. Results: T2DM developed in 6 (3%), impaired fasting glucose (IFG) in 6 (3%) and impaired glucose tolerance (IGT) in 35 (17.4%) subjects. The baseline ghrelin concentrations did not differ between the two studied groups: median fasting serum total ghrelin concentration was 733 pg/ml (25th-75th percentiles: 571-961 pg/ml) among those who maintained NGT, and 661 pg/ml (25th-75th percentiles: 527- 878 pg/ml) among those who developed IGR (IFG and/or IGT) or T2DM (p=0.421). The baseline ghrelin concentrations did not explain the changes in the 0-h or 2-h blood glucose concentrations in regression models. Conclusions: Our findings suggest that fasting serum total ghrelin levels measured at one time point might not have predictive value for the development of abnormalities in glucose tolerance.