The use of ultrasound (US) in the diagnosis of renal vein thrombosis (RVT) remains ill defined because the classical features lack specificity. The authors report three cases of renal vein thrombosis with a common US pattern: hyperechoic streaks in the interlobulary spaces confirming previous reports with the same pattern. The pattern has been observed in neonates as well as in utero. Associated vena cava thrombosis was present in two cases. This sign might be a specific sign of RVT.