In the study, 16 Morkaraman ewes were anaesthetised with 1% halothane (n = 8) and with 1.5% isoflurane (n = 8). Significant differences in respiration rate (P < 0.05) and rectal temperature (P < 0.01) during anaesthesia and total number of WBC (P < 0.05) after anaesthesia for the two treatment groups were recorded. Haematological parameters decreased compared to the values recorded before anaesthesia in both groups. However, the values (WBC, RBC, platelet counts, haemoglobin counts, PCV) were within the physiological limits. All values obtained 24 h following anaesthesia were similar to the values obtained before anaesthesia. Although the chirurgical anaesthesia was conducted with low levels of halothane, the animals recovered earlier from isoflurane than halothane anaesthesia. Isoflurane can be recommended in ewes as it caused a small alteration in the haemotological parameters during anaesthesia and recorded a shorter recovery time. (C) 2003 Elsevier B.V. All rights reserved.