OBJECTIVES The purpose of this work was to evaluate the prevalence of malocclusions and orthodontic treatment need among schoolchildren in Casablanca, Morocco. MATERIALS AND METHODS A sample of 1000 children aged between 8 and 12 years, with no history of orthodontic treatment, was chosen at random in state schools in different administrative areas of the city of Casablanca. Data was registered using the method of Bjork et al. (1964). Orthodontic treatment need was assessed with the index used by the Swedish National Board of Health (SweNBH). RESULTS We found Angle Class I malocclusions in 61.4%, Class II in 24%, Class III in 10% and an indeterminate molar class with one or more missing molars in 4.6% of the children. Overjet was 1-4mm in 63.8%, 4-6 mm in 17.2% and >6 mm in 10%. Bite was normal in 65.4%, 23.6% presented an overbite greater than 4 mm, 1.7% an anterior open bite ≤3 mm, 1.2% an anterior open bite >3 mm and 0.2% a bilateral open bite. Half of the sample presented anterior crowding, while only 2.5% presented posterior crowding. In all, 84.2% of the subjects needed some orthodontic treatment, and 15.8% needed no treatment. No statistically significant difference was found between sex or age and orthodontic treatment need (P>0.05). CONCLUSIONS This study found a strong need for orthodontic treatment, confirming the utility of implementing a programme of bucco-dental prevention and screening for malocclusion.