Based on data originating from 6 experiments with 4 treatments of varying physical structure supply in each experiment, a standard for physical structure requirement was derived for Belgian Blue bulls. The data related to the growth- and finishing period (± 340-660 kg) of 306 doublemuscled bulls. As a standard for minimal physical structure requirement 0.60/kg DM can be advised for total mixed rations, with pelleted concentrates. For non-pelleted concentrates (ground or unground) this standard can also be used, but for non-mixed rations a somewhat higher structural value should be aimed at.