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 (P0.05) 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.