Abstract: An experiment was conducted to study the hematological parameters in Fayoumi, Assil and Local Chickens of different ages reared in Sylhet region. 250 chickens of three breeds (100 Fayoumi, 50 Assil and 100 Local) were tested at different ages (1, 3, 6, 9 and 12 months) to observe the hematological parameters: i) Total erythrocyte Count (TEC) ii) Packed Cell Volume (PCV) iii) Determination of Hemoglobin (Hb) iv) Erythrocyte Sedimentation Rate (ESR) v) Differential Leukocyte Count (DLC) vi) Mean Corpuscular Volume (MCV) vii) Mean Corpuscular Hemoglobin (MCH) viii) Mean Corpuscular Hemoglobin Concentration (MCHC). Erythrocyte numbers, hemoglobin concentration and packed cell volume increased with the advancement of age in all three breeds. The TEC was higher in Fayoumi. The hemoglobin concentration was high in Assil. The PCV was slightly different or similar in all three breeds. ESR was inversely related to the age. Higher ESR in early age and lower in the advancement of age. The Fayoumi showed the higher ESR compared to other two breeds. The ESR of last two groups (9 and 12 months) of Assil and all groups of Local Chickens were negligible. Lymphocytes and heterophils were two principal leukocytes, which exert their dominance on other leukocytes. Among three breeds Local chickens possess the higher lymphocyte percentage. The heterophils were higher in Fayoumi breed. Monocyte was lower in Assil and Local chickens. Eosinophils were higher in number in local and Assil compared to Fayoumi. Higher MCV was recorded in Local chickens followed by Assil and Fayoumi chickens. MCH values were near about similar in Assil and local chicken but lower in Fayoumi breeds. The MCHC values of all three breeds were almost nearer to each other. The above study has highlighted some of the normal hematological parameters of chicken mostly reared in Sylhet region. However, more detailed study could be conducted in this regards.