Objective: The standardization of measurement of orthodontic treatment complexity and need will in no doubt facilitate international comparisons of such facets of orthodontic provision as there could be some variations across the globe. The objective of the study was to assess the orthodontic treatment complexity and need in a referred orthodontic centre in Nigeria, using the new international orthodontic index – the Index of Complexity, Outcome and Need (ICON). Methods: Fiftysix (56)pre-treatment study models were retrospectively selected from the model store of the orthodontic clinic at the University College Hospital, Ibadan, Nigeria without special considerations for age and gender. Descriptive statistics were employed in the data analysis. Results: Treatment was considered needful in 47 (83.9%) of the sample. Thirtyfour (60.7% cases) were classified as difficult or very difficult. Only 1 (1.8%) and 13(23.2%) belonged to the easy and mild categories, respectively. The overall mean ICON score was 67.38 + 19.63 SD (range 25-104). Conclusion: Considerable proportions of these referred orthodontic cases in Nigeria needed treatment and had treatment complexity comparable to the Caucasians.