An 11-year-old, neutered male, Vietnamese pot-bellied pig was admitted for routine dental and foot care. As a part of routine geriatric evaluation, blood was submitted for a complete blood count and serum biochemical analysis. The blood count revealed a marked leucocytosis due to lymphocytosis. Further diagnostic evaluation, including abdominal and thoracic radiography, abdominal ultrasonography and blood lymphocyte immunophenotyping confirmed a diagnosis of chronic lymphocytic leukaemia of T-cell origin. Treatment was initiated with oral prednisone and cyclophosphamide. The pig did well on treatment for about 1 month after discharge but was then euthanized.