Abstract The present paper reports the case of a 3 years old, female Bearded Dragon (Pogona vitticeps) presenting lethargy, anorexia, weight loss, and anemia and marked leukocytosis at CBC. The majority of leukocytes were lymphocytic/lymphoblastic cells (97%). Immunocytochemical staining of blood smears marked for CD3 (neg) and CD79a (pos) suggested immunophenotype B. The patient died after one month from diagnosis. Histology evidenced lymphoid infiltration in the heart, spleen, liver, kidneys and gut. In addition, in the bone marrow a massive infiltration of lymphoid cells confirmed the diagnosis of leukemia. Immunohistochemistry confirmed the CD79a positivity of a large part of infiltrating lymphoid cells indicating a B cells immunophenotype of the neoplastic population. The presence of lymphocytosis and multiorgan infiltration supported the diagnosis of lymphocytic leukemia. Finally, a revision of the literature has also been made.