Objectives:The nutrition transition in developing countries has resulted in the "nutrition paradox" where both under-and over-nutrition exist in the same population. This phenomenon is scarcely reported in Nigeria. The prevalence of thinness and overweight/obesity was therefore studied in Umuahia, Nigeria using two international references and the results compared. Subjects and Methods: A total of 1911 children and adolescents (51.3% females) were recruited and anthropometric data obtained from them using the standard procedures. Age was determined from each subject's school records. Overweight, obesity, and thinness (stages 1-3) were defi ned using the Cole et al. International surveys (IS) and the World Health Organization (WHO) study references. Appropriate statistical analyses were carried out on data generated. Results: As much as 24.2% of the boys and 19.2% of the girls were thin, based on the WHO standards, whereas, 17.3% of the boys and 15.5% of the girls were thin based on the IS standard. A total of 4.9% of boys and 9.2% of girls (WHO); and 3.9% of boys and 5.8% of girls (IS) were overweight. Obesity was found in 1.1% and 1.8% of the boys and girls respectively (WHO); and 0.3% and 1.0% of the boys and girls respectively (IS). Irrespective of age, there were no signifi cant differences (P0.05) between the proportions of the population diagnosed with thinness, overweight or obesity by the two standards used. Conclusion: Under-and over-nutrition, typifi ed by thinness and overweight/ obesity respectively co-exist in the studied population. The IS and WHO reference methods give statistically similar estimates of the nutritional status in this population.