A 76-year-old man was admitted with a first episode of deep vein thrombosis (DVT) of his left leg. It was associated with a distended urinary bladder, due to benign prostatic hypertrophy. Screening for malignancy was negative. Laboratory testing revealed protein S deficiency. Although a distended bladder may induce venous stasis, it is not a proven risk factor for DVT. Clinical expression possibly depends on the concomitance of other risk factors, such as inherited or acquired thrombophilic defects. However, it is also possible that the association of a distended bladder with DVT of a lower limb has not been recognised yet. As a distended bladder is rather common in elderly men, a proper study is warranted to estimate the prevalence of associated DVT.