Abstract: Two experiments were described in which sixty one-day old (IPA) chicks were distributed into four equal groups, three for treatment & the other for control. Ampicillin, Enrofloxacine or Amoxicillin were used for five consecutive days via drinking water for treatment for at the first and twenty second day of life. Five birds from each group were slaughtered on 6 and 28 days post treatment and hematological examinationsperformed on blood samples collected just prior to slaughter. Changes in PCV, HB, RBC, WBC, MCV, MCH and MCHC were observed. The investigations demonstrated a fall in hematological values in body chicks, Whereas in older ages these values were analogous with normal ranges. The changes were not substantiate the presence of anemia. They might be an indications of an incidental haemodilutionin the hematological observed in this study.