The aim of the present study was to compare the impact on blood pressure and different metabolic parameters of a weight-loss program on obese dogs fed on a low-fat high-fibre diet and treated with and without mitratapide. The study sample consisted of 36 obese dogs, randomly assigned to a control group (n=17), which were fed on a low-fat high-fibre diet, and an intervention group (n=19), fed on the same diet and treated with mitratapide. Variables measured included body condition score, body weight, heart rate, systolic and diastolic blood pressures; total cholesterol, triglycerides and glucose levels; alanine aminotransferase and alkaline phosphatase activity, measured both at baseline (day 0) and at the end of the weight loss program (day 85). All the studied parameters had decreased in both groups at the end of the study; these being diastolic blood pressure, total cholesterol and alanine aminotransferase, significantly lower in dogs treated with mitratapide. The use of mitrapide in addition to low-fat high-fibre diet does not seem to offer any further useful effect in the loss of weight during the treatment of canine obesity. On the other hand, mitratapide seems to present certain beneficial effects on pathologies associated with obesity, these being mainly related to blood pressure, lipids and hepatic parameters.