Diagnostic imaging after renal transplantation is of high importance in the differential diagnosis of peri- and postoperative complications. Sonography with color duplex imaging is the method of choice in the diagnosis of acute transplant rejection. MRI is an additional method in the diagnosis of transplant dysfunction especially in diagnosis of perirenal fluid collections. MR angiography and MR urography are noninvasive diagnostic modalities with the potential to replace angiography and pyelography. Angiography, complemented by carbon dioxide angiography, still is the gold standard in the diagnosis of transplant artery stenosis.