This study proposes antibiotics addition to the culture broth to explore an alternative method of sterilization for axenic cultivation of Haematococcus pluvialis. As a preliminary experiment, bubble column photobioreactors (400 mL working vol.) were operated in both open and closed modes, resulting in two times higher productivity in the closed systems. When different antibiotics were added to the open systems, the productivity of the open system was improved in some cases. For the cultures grown with griseofulvin or ampicillin, the maximum cell concentrations were comparable to that obtained for the sterilized closed culture, which was 10~30 % higher than that of the open unsterilized culture. Furthermore, the astaxanthin accumulation and the average cell size of the cultures grown under these antibiotics were much smaller than those under the open system, which clearly indicated that these antibiotics did not have any adverse effects on the growth of H. pluvialis. Although the productivities under these open cultures with griseofulvin or ampicillin were lower than that of the sterilized closed system with no antibiotics, the results reported here indicate that supplementation of suitable antibiotics can reduce the contamination to a certain degree without affecting growth or other metabolism; thus, it can be an alternative method of sterilization for axenic cultivation of H. pluvialis.