The nutcracker syndrome is associated with left renal vein compression in its passage between the abdominal aorta and superior mesenteric artery. This phenomenon can cause left renal vein hypertension manifested by abdominal pain, hematuria, and pelvic congestion syndrome. The diagnosis is essentially clinical, supported by imaging and necessarily one of exclusion. The literature suggests that it occurs with a reasonable prevalence in children who present with isolated hematuria but is commonly misdiagnosed. We describe two clinical cases of children with hematuria whose investigation led to the diagnosis of Nutcracker Syndrome. In the presence of hematuria of unknown origin it's necessary to consider this entity, highlighting the essential role of a noninvasive test such as renal ultrasound with Doppler in its diagnosis.