In this study, the effects of surgery and general anaesthesia that is with xylazine -ketamine hydrochloride and xylazine-pentobarbital sodium used commonly in carnivore, on the blood glucose levels, were investigated. The study was carried out in two groups, that each was consist of 5 dogs. The investigation was carried out in two parts. In the first part, the animals in the first group were anaesthetized with xylazine -ketamine hydrochloride and the animals in the second group were anaesthetized with xylazine-pentobarbital sodium. In the second part, the same animals used in first part were anaesthetized with the same anaesthetic combinations, and than experimental laparatomie was made. In the both parts, 1-2 ml blood samples were taken from animals before anaesthesia and operation then on the 30 th, 60 th, 90 th, and 120 th minutes after anaesthesia and operation. Glucose values were detedmined with spectophotometer. As a result, it may be said that pentobarbital sodium used in study has no hyperglycemic effect, but xylazine and ketamine hydrochloride has significant hyperglycemic effect.