Summary: The hooves of Mangalarga Marchador horses, the largest equine breed in Brazil, are commonly trimmed with long toes to create more animation to their typical gait called marcha. With the hypothesis that long toes cause radiographic changes in the feet, which correlate with proximal suspensory ligament dimensions, the aim of this study was to determine radiographic measurements values of front hooves and correlate them with cross sectional area (CSA) values of the proximal suspensory ligament in Mangalarga Marchador horses subjected to athletic training. Two mares and 18 geldings, 3 -10 years of age (5.8 ± 2.7 years old) were used. Both forelimbs were examined radiographically in lateromedial views and measurements of 14 parameters of interest of each foot were obtained with Metron Hoof Pro Software. Ultrasonographic images were obtained from the proximal suspensory ligament at a distance of 4 and 8 cm from the accessory carpal bone with standard ultrasound technique with the limb in a weight bearing position to determine the CSA. Correlation between hoof and suspensory ligament variables were evaluated using the correlation Pearson test (P < 0.05). All horses had a broken back hoof pastern axis, and 59 % of them were found to have underrun heels, indicating a high risk for lameness development. However, no significant correlation between hoof measurements and CSA of the proximal suspensory ligaments was found (P > 0.05). Although the effects of long toe trimming could be characterized with hoof radiographic measurements, no evidences of proximal suspensory ligament stress could be detected in this horse population.