A 4 mo old intact male Labrador retriever was referred to the authors’ institution for a 3 wk history of weight loss and progressive abdominal distension. Thoracic radiographs revealed sternal lymphadenopathy and a diffuse unstructured interstitial and bronchial pulmonary pattern. An abdominal ultrasound revealed multifocal lymphadenopathy, hepatosplenomegaly, and biliary duct dilation. Fine-needle aspirates of the spleen and liver revealed Histoplasma capsulatum organisms. Antifungal therapy was initiated with itraconazole and terbinafine. Repeat ultrasound examinations revealed resolving hepatosplenomegaly and resolving cystic duct dilation. Ultrasonographic findings mirrored a decrease in urine H capsulatum antigen levels. Histoplasmosis should be considered as a differential for unexplained biliary duct dilation or obstruction in dogs. Dogs with disseminated histoplasmosis should be monitored for this potential complication.