Radiological investigations complete echographic data by valuable information about the functional status of kidneys. Intravenous urography is less sensitive than echography in little and big cysts dimensions’ determination (≤3 cm and ≥7 cm in diameter). Radiopharmaceutical substance elimination disturbances correlate with increased hospital stay, hematuria and proteinuria in affected patients. Bigger cysts have a tendency to provoke urine elimination problems. In the same time the cyst localization does not correlate with such problems. It could be concluded that the urine elimination disturbances are probably caused by calices and pyelic functional deficits rather than by direct intervention of mechanical factor. Renal echography sensibility and sensitivity were quite similar to those of computed tomography in the simple renal cyst’s localization and dimensions’ determination. Therefore, computed tomography should be reserved to the cases of the simple renal cyst associated with difficult differential diagnosis and/ or surgical approach problems.