This article takes into account the diagnostic reliability of ultrasounds (US) in the ureteral lithiasis localisation. A stone has been ultrasonographically localised in 82.3% of 119 patients, this rate rising up to 89.4% in the last 85 consecutive patients. From a clinical point of view, 104 patients presented renal signs, whereas 10 out of them showed an atypical symptomatology, which at first led to a suspicion of acute appendicitis (5), intestinal obstruction (4), acute pancreatitis (1). A stone was accidentally detected in five asymptomatic patients. In 80% of the cases, the stone was situated in the proximal or juxtavesical ureter; in 20%, in the middle or distal ureter. A particular stress is laid in the ultrasonographic follow-up, by which the stone was uncovered in 6 cases, at first considered negative at US. Eight patients had to be referred to treatment with ESWL.