A method of making customized orthodontic brackets. The method has steps of providing a plurality of customized orthodontic bracket precursors, providing one or more support structures, positioning the bracket precursors by means of the support structure(s) in a machining device and using the machining device to provide an archwire slot in each bracket precursor by material removal with the archwire slots aligned along a common path with each other. The invention helps minimizing efforts in the manufacturing and provides the brackets with a precise archwire slot.