The present paper describes 3 cases of classical thrombasthenia and 3 cases of combined platelet factor 3 defi- 3 ciency and absence of platelet aggregation. The bleeding time and the clot retraction in the latter 3 patients were They, however, did not differ in clinical presentation of classical thrombasthenia. These cases have been designated as thrombopathic thrombasthenia. The possibility of an in vivo platelet activation leading to variable amounts of platelet factor 3 release in thrombasthenia has been raised. Mechanism of PF3 release in vivo in thrombasthenia, however, is not known and needs further study.