The aim of this study was to combine the estimated intensity of acute stress experienced by cats in the veterinary clinic with the assessment of serum cortisol, adrenaline, noradrenaline, glucose and platelet counts. The authors aimed to answer the question of whether the generally known acute stress markers correlate with the degree of stress experienced by cats in the veterinary clinic. Fifty clinically healthy cats were studied. Behavioural assessment of stress was performed according to the modified criteria indicated by Kessler and Turner under conditions of minimal stress recommended for veterinary medicine. Serum levels of cortisol, adrenaline, noradrenaline, glucose and platelet count were determined by recognized and commonly used methods. The cats examined in the clinic were divided into 3 groups according tothe type of stress reaction. In 8 (16%) cats, the behaviour was “relaxed”, 25 (50%) cats showed “tense” stress reactions, and in 17 (34%) cats, strong reactions of fear were noted. Serum levels of cortisol, adrenaline, noradrenaline, glucose and platelet count differed between the groups, but the differences were not statistically significant and did not correlate with the degree of acute stress in cats. It is concluded that a large number of cats (84%) experience stress in the clinic and that the working methods of veterinary teams should be further improved to minimize it. When cats exhibit less fear during veterinary examinations, their owners are more likely to schedule examinations, and veterinarians are more likely to obtain accurate measures during the examination, which improves the overall welfare of the cat. Another conclusion is that the biochemical parameters tested did not meet the conditions to be treated as measures of acute stress in cats. Therefore, further research is needed to find indicators associated with the degree of acute stress in cats.