The objective of this study was to compare in clinical patients the analgesic effect of the centrally acting analgesics tramadol and buprenorphine in continuous intravenous anaesthesia (TIVA) with propofol. Twenty dogs undergoing prophylactic dental treatment, aged 2−7 years, weighing 6−27 kg, were included in ASA I. and II. groups. Two groups of dogs received intravenous (IV) administration of tramadol hydrochloride (2 mg.kg−1) or buprenorphine hydrochloride (0.2 mg.kg−1) 30 minutes prior to sedation, provided by midazolam hydrochloride (0.3 mg.kg−1) and xylazine hydrochloride (0.5 mg.kg-1) IV. General anaesthesia was induced by propofol (2 mg.kg−1) and maintained by a 120 minutes propofol infusion (0.2 mg.kg−1min−1). Oscilometric arterial blood pressure (ABP) measured in mm Hg, heart rate (HR), respiratory rate (RR), SAT, body temperature (BT) and pain reaction elicited by haemostat forceps pressure at the digit were recorded in ten minute intervals. The tramadol group of dogs showed significantly better parameters of blood pressure (P < 0.001), lower tendency to bradycardia (P < 0.05), and better respiratory rate (P < 0.001) without negative influence to oxygen saturation. Statistically better analgesia was achieved in the tramadol group (P < 0.001). Tramadol, in comparison with buprenorphine provided significantly better results with respect to the degree of analgesia, as well as the tendency of complications arising during anaesthesia.