Inia geoffrensis is an endangered species of the Amazon River basin, but there has been limited research regarding its health, particularly in describing normal cell morphology by traditional techniques. This study aimed to identify the peripheral blood cells of I. geoffrensis through microscopic evaluation. Blood smears were collected from wild adults and stained with Wright's stain. We differentiated leukocyte cells (neutrophils, eosinophils, lymphocytes, and monocytes) and platelets. Additionally, we observed signs of inflammatory reactions in cell morphology by incrementing cell size and active cytoplasm in neutrophils, eosinophils, lymphocytes, and platelets. These findings provide important considerations for hemogram interpretation in future research and individual clinical cases in Amazon River dolphins. Also, our study delivers baseline information for future characterization and understanding of hemogram and leukogram changes in response to disease and health assessment for dolphin species.