The role of platelets in primary hemostasis involves their adherence to sites of vessel injury, activation, secretion of platelet granule content, and finally, aggregation to form the primary hemostatic plug. Under physiologic conditions of vascular flow, these processes require the synergistic action of several proteins and platelet receptors, and also the action of physiological agonists that stimulate the activation of the platelets. As a result, hereditary mutations of genes codifying for molecules and surface receptors implied in primary hemostasis will be expressed as hemorrhagic disorders, including von Willebrand disease, Glanzmann thrombasthenia, Bernard Soulier syndrome, storage pool diseases, among others. The diagnosis of these diseases is possible through platelet function assays that resemble the physiological processes of activation, adhesion, release of granule content, and aggregation. Platelet aggregometry is one of the most frequently used tests. This review article intends to describe the utility of platelet aggregometry for the diagnosis of hereditary hemostatic disorders and sticky platelet syndrome, a hereditary thrombotic disorder characterized by increased platelet aggregability. In addition, the fundamentals of the test, the pre-analytical, analytical and post-analytical conditions, the test indications, contraindications and results interpretation are discussed.