Ten-day-old northern bobwhite quail and mallards were inoculated orally and intravenously with Salmonella pullorum at concentrations of one thousand to 10 billion colony-forming units/ml. The bacterium was found to be extremely virulent in young bobwhite during two experiments with 65-100% mortality; however, no mallards died or exhibited any signs of morbidity. Blood chemistry values and antibody titers of bobwhite were inconclusive due to high mortality rate. Significant differences (P<0.05) were observed in serum calcium, uric acid, and lactate dehydrogenase values of treated mallards, and antibody titers were detected as early as one week following inoculation in a pilot test. The bacterium was cultured from bobwhite feces and from liver, lungs, heart, kidneys, pancreas, and spleen tissues removed at necropsy; however, it was isolated only from liver tissue of four mallards. Tissues submitted by histopathological examination showed bobwhite to be severely affected. Small bacterial colonies were frequently found in the capillaries of various organs of the bobwhite, particularly in the heart and kidneys. Mallard tissues were found to be essentially normal except for slight vacuolar changes in the liver.