ln this study, 50 white leghorn cocks which were at the same age, similar body weight and healthy were used. The animals were divided into 5 groups as Control, Group ST, Group AA, Group ASA₁ and Group ASA₂. The groups were placed into different coops. In the coops, while it was 40 dm² floor area to control animals for one bird, it was 10 dm² floor area to the animals in the other groups for one bird. During the experiment, while ascorbic acid was added in the ration of the animals in the Group AA, acetylsalicylic acid was added in the ration of the animals in the Group ASA₁ and Group ASA₂ at the different dose levels. Because of the increase in the ratio of circulating heterophils to lymphocytes (H/L), in the animals except control ones were determined to occure stress. The mean of red blood cell (RBC), haemoglobin amount (Hb), hematocrit values, the values of erytrocyte sedimentation rate (ESR) at 1st, 2nd, 24th hours, thrombocytes and white blood cell (WBC) count, proportions of heterophils, eosinophils, basophils, monocytes and lymphocytes, H/L ratio in control animals were determined to be 2. 899x106/mm3, 8. 24 gr/ dl, 28. 30 %, 2. 56 %, 1. 58 %, 65. 84 % and 0. 43 respectively. In the animals of Group ST, the mean of lymphocyte, eosinophil, basophil proportions and ESR at 2nd, 24th hours decreased (54. 90 %, 0. 64 %, 1. 20 %, 46. 12 mm and 113. 76 mm respectively). However, the mean of H/L ratio, heterophil proportions, RBC and WBC counts, Hb and hematocrit values increased (0. 77, 41. 38 %, 3. 448x10⁶/mm³, 36. 58x10³/mm³, 10. 56 gr/dl and 32. 26 % respectively). The mean of H/L ratio, lymphocytes, eosinophil, basophil, heterophil and monocytes proportions, RBC, WBC and thrombocytes counts, Hb, hematocrit values, ESR at 1st, 2nd and 24th hours in the animals those were given ascorbic acid were found to be 0. 51, 63. 22 %, 0. 92 %, 2. 04 %, 32. 08 %, 1. 88 %, 1. 151x10⁶/mm³, 33. 00x10³/mm³, 0. 4664x10⁵/mm³, 9. 59 gr/dl, 30. 22 %, 24. 78mm, 47. 34mm and 115. 46 mm respectively. On the other hand, in the cocks of Group ASA₁, the same values were determined to be 0. 61, 59. 72 %, 0. 80 %, 1. 64 %, 35. 82 %, 2. 02 %, 3. 332x10⁶/mm³, 35. 74x10³/mm³, 0. 4696x10⁵/mm³, 10. 18 gr/dl, 31. 92 %, 24. 64mm, 46. 66mm and 113. 52mm respectively. Whereas, the same values in the animals of Group ASA₂ were found to be 0. 70, 57. 00 %, 0. 72 %, 1. 84 %, 38. 72 %, 1. 72 %, 3. 386x10⁶/mm³, 36. 52x103/mm3, 0. 4688x10⁵/mm³, 10. 30 gr/dl, 32. 02 %, 24. 63 mm, 46. 98 mm and 114. 74 mm respectively. Based on results, it was concluded that some haematological parameters was influenced by stress and ascobic acid was more effective agent than acetylsalicylic acid on stress in poultry.