Renal artery embolism (RAE) is a rare disease. Urgent treatment is necessary, as ischaemia can cause irreversible kidney damage in 60 to 90 minutes. RAE frequently clinically manifests as a pain similar to renal colic. Source of embolus is predominantly the heart at atrial fibrillation. Laboratory findings are unspecific. Ultrasonography with color Doppler imaging is essential. Kidney perfusion is low and upper urinary tract is undilated. Renal function can be recognized by intravenous urography and at renal scintigraphy. In angiography, renal artery is closed with thromboembolus. With no delay, transcatheter clot aspiration should be performed and fibrinolytic agents (tissue plasminogen activator) should be topically administered. Continual heparinisation and later warfarinisation should follow. In spite of successful revascularisation, parameters of kidney function can almost never reach that prior the RAE and shrinkage of kidney becomes a frequent consequence. Treatment can be successful even in patients with renal occlusion lasting over 90 minutes, since occlusion is often incomplete or significant collateral blood supply exists. In conclusion, renal artery embolism must be considered in cases of flank pain in patients with certain risk actors (especially atrial fibrillation). Ultrasonography with color Doppler imaging and urgent angiography of the renal artery are necessary in these cases. Thromboembolus can be then aspirated, and kidney perfused with fibrinolytic agent.