An eight year old, male castrated Basenji presented to the Cornell University Hospital for Animals Emergency Service for a one week history of unusual licking and swallowing behavior. On the day of presentation, the owner also noticed melena and gingival bleeding. A severe thrombocytopenia was discovered in the dog. Bone marrow aspirate cytology revealed an absence of megakaryocytes. The resultant diagnosis, amegakaryocytic thrombocytopenia, is an uncommon disease in the dog. This case report describes the historical features, physical examination findings, diagnostic testing, treatment, and outcome for amegakaryocytic thrombocytopenia in this dog.