Nitric oxide (NO) and carbon dioxide (CO2) were simultaneously eliminated from a model flue gas using a marine microalga, strain NOA-113, cultivated in a long tubular photobioreactor. About 40 mg of NO and 3.5 g of CO2 were eliminated per day in a 4-l reactor column with aeration of 300 ppm (v/v) NO and 15% (v/v) CO2 in N-2 at a rate of 150 ml/min. This reactor system is thought to be suitable for evaluating NO elimination by microalgae. The effects of NO concentration, gas flow rate, and Light conditions on NO elimination were investigated using this system.