We evaluated the feasibility and treatment performance of a continuous feeding and intermittent discharge (CFID) bioreactor treating real hospital wastewater with the emphasis on simultaneous carbon, nitrogen and phosphorus (CNP) removal. The experiments were based on a central composite design (CCD) and analyzed by response surface methodology (RSM). To analyze the process, three significant variables, aeration time (2-4 h), mixing time without aeration (30-90 min) and MLSS concentration (2,000-6,000mg/l), were studied. Results show that an increase in aeration time increased the nitrogen and phosphorous removal efficiency. However, when the aeration time was more than 3 h, the efficiency of phosphorous removal was decreased due to insufficient acidification. A similar scenario was observed when mixing time was increased for phosphorus and nitrogen removal efficiency. MLSS had a positive effect on all the responses. Under optimal conditions, the concentrations of quality parameter in the influent in average were recorded as 586 mg COD/l, 296mg BOD5/l, 97mgTN/l and 16.47mg TP/l, which yields the following removal efficiencies, 95.6%, 98.3%, 88.0% and 92.0%, respectively.