Background: Use of telmisartan for the treatment of proteinuria in dogs has not been thoroughly investigated.Hypothesis/Objectives: Telmisartan can be effective for the treatment of proteinuria in dogs.Animals: Forty-four client-owned dogs with proteinuria.Methods: Retrospective study. Dogs diagnosed with clinically relevant proteinuria (nonazotemic dogs with a urine protein-to-creatinine ratio [UPC] ≥2 and azotemic dogs with UPC ≥0.5) were separated into 3 groups: telmisartan alone, with benazepril, or with mycophenolate. The UPC was recorded before treatment and at subsequent follow-ups (1, 3, 6, and 12 months, as available). Response to treatment was categorized as complete (UPC <0.5), partial (UPC decreased by ≥50% but still ≥0.5), or no response (UPC decreased by <50%). Serum creatinine and potassium concentrations and arterial pressure also were recorded.Results: In the telmisartan group, treatment response (UPC <0.5 or decreased by ≥50%) was observed in 70%, 68%, 80%, and 60% of dogs at 1, 3, 6, and 12 months follow-up, respectively. No significant changes were noted in serum creatinine or potassium concentrations, or in arterial blood pressure at all follow-up times. Adverse effects consisted of mild self-limiting gastrointestinal signs in 5 dogs. Two dogs developed clinically relevant azotemia that required discontinuation of the treatment before the first follow-up.Conclusions and Clinical Importance: Telmisartan can be considered for treatment of proteinuria in dogs, alone or in combination with other treatments for proteinuria.angiotensin receptor blocker, canine, renin-angiotensin-aldosterone system, urine protein : creatinine ratio | INTRODUCTIONPersistent renal proteinuria is associated with increased renal morbidity and increased mortality in dogs and cats. [1][2][3] The renin-angiotensinaldosterone system (RAAS) regulates blood pressure, fluid and Abbreviations: ACEi, angiotensin converting enzyme inhibitors; ACVIM, American College of Veterinary Internal Medicine; ARB, angiotensin receptor blocker; AT1, angiotensin II type 1 receptor; AT2, angiotensin II type 2 receptor; RAAS, renin-angiotensin-aldosterone system; SCr, serum creatinine concentration; TOD, target organ damage; UPC, urine protein : creatinine ratio.