Abstract: Considering the spleen great importance for the immune system and the role of this organ in response to Feline Leukemia Virus (FeLV) infection in response to Feline Leukemia Virus (FeLV) infection, the objective of this study was to evaluate spleen histomorphometric changes, as well as its weight and volume. Furthermore, lymphocytes were quantified and the VEGF system expression was analyzed, especially its VEGF-A protein, which is part of physiological angiogenesis in different body organs. Spleens of infected and non-infected cats of six months to three years old were collected and used for confection of histological slides, which passed through the coloration process and immunohistochemistry technique. We observed state of splenomegaly, however, there were no statistically significant histomorphometric changes. Presence of lymphocytes was significantly reduced in the diseased group when compared with the control. On the other hand, there was a statistically significant increase in the VEGF-A protein expression.