Echinocytes were evaluated quantitatively in both healthy and sick dogs and compared with red blood cell (RBC) morphology on Wright's-stained blood smears. Of 68 samples submitted from sick dogs, 32 had high echinocyte numbers. Two diseases, glomerulonephritis and lymphosarcoma, accounted for 15 of the 32 cases. In only four instances were echinocytes reported from blood smear evaluation and not found to be high by quantitative studies. We conclude that nonartifactual echinocytosis occurs in the dog and that it may be associated with specific diseases.