Triploid cherry salmon (Oncorhynchus masou) were induced by the heat shocking treatment of fertilized eggs 10 minutes post fertilization at $28^{circ}C$ for 15 minutes. Haematological and physiological characteristics of diploid and the induced triploid fish were examined just before the spawning period. Triploids had significantly lower concentrations of circulating red blood cells than that of diploids (P<0.01). However, oxygen consumption, hematocrit, hemoglobin, RBC, and mean concentration of hemoglobin within the RBC of triploids were higher than those of diploids. The concentrations of total protein, albumin and cholesterol from triploids were also higher than those from diploids.