Abstract. Uses of fixed appliance have become popular recently. The purpose of its use is to correct malposition of teeth in order to normalize the masticatory function and to eliminate the accumulation of food remain between the teeth. These will prevent the formation of caries and any periodontal tissue disease. Fixed appliance patients must routinely maintain their oral hygienes. This study was an analytical survey with cross-sectional design to know the relationship between behaviour in tooth brushing of students using fixed appliance and oral hygiene in Poltekkes Kemenkes Medan. The avarage of OHI-S value of students using fixed appliance was still above national target (2.68) and there was a relationship between behavior in tooth brushing of students using fixed appliance and oral hygiene (p<0.02). In conclusion, to get good oral hygiene and to prevent caries formation and periodontal disease patients using fixed appliances should maintain their dental health.