An intact male terrier dog aged 6.25 years was referred with a history of dysuria and intermittent hematuria for the past 2 years. Clinical examination, abdominal radiography and ultrasonography revealed the presence of prostatomegaly and cystolithiasis. A large radio-opaque calculus was observed inside the urinary bladder and ultrasonographic size of the prostate gland was [Formula: see text]. The animal was diagnosed with benign prostatic hyperplasia based on anamnesis, physical examination findings and paraclinical investigations. The presence of a single large calculus within the urinary bladder was associated with incomplete voiding resulting from enlargement of the prostate. The bladder calculus which was removed by cystotomy was a mixed type of stone consisting of ammonium (10%), phosphate (20%), calcium (20%), oxalate (40%) and magnesium (10%). The enlargement of the prostate gland was also confirmed by intraoperative examination. Cystolithiasis associated with canine benign prostatic hyperplasia has not been previously reported in the literature.