Abstract: Salmonella Gallinarum is the agent of fowl typhoid in poultry causing significant economic losses in poultry production. The present study was conducted to investigate the effect of experimental infection of one-day-old broiler chicks with locally isolated Salmonella Gallinarum strain (the cause of acute fowl typhoid disease) on hematological and biochemical constituents. One hundred and forty broiler chicks -one day old were randomly divided intotwo groups. The first group (N=50) was kept as a normal control. It was inoculated with 0.2 ml of sterile saline through crop gavage. The second group (N=90) was infected with isolated Salmonella Gallinarum strain at a dose 0.2 ml of sterile saline containing 3×10 CFU/ml through the same route. After inoculation, all experimental birds were kept under strict daily observation for recording clinical signs and mortality rates. Five blood samples were collected from each group at the zero time, 2 , 4 , 7 , 14 , 21 and the 28 day post infection for determination of hematological and serum biochemical parameters. The infected group showed clinical signs (dullness, ruffled feathers, droppings, huddled together, white pasty diarrhea, loss of appetite, decrease in feed intake and depression), mortality rate (24.4%), macrocytic hypochromic anaemia, leuckocytosis, heterophilia, significant hypoprotinemia, hypoalbuminemia, hypoglobulinemia and marked decrease in the serum iron level, in addition to marked increase in the activities of aspartate aminotransferase and alanin aminotransferase and the levels of creatinine and uric acid. In conclusion, the experimental Salmonella Gallinarum infection induced acute anaemia, leukocytosis, heterophilia, lymphopenia and alteration in the liver and kidney functions.