Biliary sludge is frequently detected during abdominal ultrasonography in dogs, yet its clinical significance and optimal nutritional management remain uncertain. Sludge often persists over time, and impaired gallbladder emptying has been reported in affected dogs.(1,2) This retrospective case series described ultrasonographic and clinicopathological outcomes in ten client-owned dogs with biliary sludge following implementation of individually formulated, nutrient-controlled fresh-food diets. Records were reviewed for signalment, previous diet, body weight, concurrent medication, dietary composition, ultrasonography and available biochemical results. Formulations provided 31.5–46.9% protein, 7.8–10.9% fat, 4.5–9.4% fibre and 0.20–0.44% taurine on a dry-matter basis, with energy densities of 0.86–1.08 kcal/g. All dogs received high-moisture fresh-food meals at least 2-3 times daily (at lease 3 meals per day), with no intermeal interval exceeding 10 h. Seven dogs received no concurrent hepatobiliary medication, two received ursodeoxycholic acid and one received another hepatobiliary preparation. Follow-up ultrasonography demonstrated complete sludge clearance in six dogs, near-complete clearance in two and marked improvement in two. All seven dogs receiving no concurrent hepatobiliary medication improved ultrasonographically. Where longitudinal biochemical abnormalities were available, changes included normalisation of alanine aminotransferase activity and serum triglyceride concentrations and substantial reduction in total bile acids. Improvement occurred in dogs undergoing weight loss, weight maintenance and slight weight gain. The narrowest macronutrient range across formulations was dietary fat, suggesting controlled fat intake as a candidate characteristic for future study; however, protein, fibre, taurine, ingredients and energy intake were modified concurrently. Biliary sludge can persist in dogs and may progress in a subset of cases, supporting longitudinal ultrasonographic assessment.(1,3) Implementation of a quantitatively formulated, controlled-fat fresh-food dietary strategy was temporally associated with ultrasonographic improvement in all ten dogs. Because this uncontrolled retrospective series cannot distinguish dietary effects from spontaneous variation, concurrent medication, weight change or other clinical factors, the findings should be considered hypothesis-generating. Prospective controlled studies using standardised sludge scoring and predefined dietary protocols are warranted to determine whether specific nutritional characteristics influence biliary sludge persistence and gallbladder function in dogs.