Pituitary-dependent hyperadrenocorticism (PDH) was diagnosed with history taking, physical examination, complete blood count, serum chemistry profiles, abdominal radiology, ultrasonography and adrenal function tests in 3 dogs. Their clinical signs were polyuria, polydipsia, polyphagia, bilateral symmetrical truncal alopecia and secondary infection in skin or urinary tract. Especially one dog showed severe clinical signs such as calcinosis cutis and delayed wound healing. These 3 dogs were diagnosed as PDH, and treated with selegiline 1-2 mg/kg /ay sid PO. 2 dogs with clinical signs of PDH were disappeared and improved, but 1 dog with severe illness progressed gradually despite of selegiline and mitotane application, and eventually died.