Glanzmann's thrombasthenia was reported and described as a bleeding diathesis seen in children and characterized by diminished clot retraction. It is an autosomal recessive bleeding disorder. The disease is marked by frequent mucocutaneous hemorrhages either due to defective function of the platelets or lack of fibrinogen binding membrane receptor glycoproteins IIb/IIIa which are located on the surface of the platelets. Case reports on 3 siblings, a girl of 11, and 2 boys of 12 and 16 years old with Glanzmann's thrombasthenia are reviewed. The major complaint of the patients was gingival bleeding. Periodontal treatment was performed under platelet transfusion and proper oral hygiene instruction was given. The patients were followed for 6 months and no periodontal complications developed during this time. Proper periodontal care for such patients is essential both for local and systemic health.