Acute severe colicky pain in the flank region is termed as renal colic (RC), which is commonly diagnosed and treated in the emergency department (ED). The present study is designed to investigate the hospital costs of patients with RC admitted to the ED and factors affecting the figures. Retrospective analysis includes all patients diagnosed with RC following physical examination and X-ray, ultrasound, computed tomography together with laboratory investigations in the university-based ED between February 2007 and February 2009. The study included 574 patients eligible for the predefined criteria. Mean total hospital cost in patients admitted to the ED due to RC was calculated to be 55.77 Euro. The greatest contribution to the total cost was made by radiological investigations in the ED (40.5%) followed by treatment costs (19.7%). Size and location of the stone and stay times in the ED were the independent variables affecting the costs. The costs were higher as the stones were bigger and as they were more distal in the ureter. Renal stones were associated with the lowest hospital costs. Radiological investigations are the greatest contributors in the ED costs in patients with RC. Effective measures need to be undertaken to reduce resultant costs. Preventive measures as well as diagnostic and therapeutic procedures should be standardized in the ED in accordance with technological advances and also cost-effectiveness when appropriate.