Polycyclic aromatic hydrocarbons (PAHs) are well known as one of toxic environmental pollutants and can be eventually accumulated in marine sediments. Due to those potential hazardous effects on ecosystem, removal of PAHs from marine sediment has been great concern. In this study, we optimized the fed-batch parameters in bioslurry reactor. The effect of cyclodextrin on the degradation rate of PAHs was also considered with simultaneous measurement of the proportion of PAHs-degrading bacteria using T-RFLP method. The activity of electron transport system (ETSA) in the first batch was increased from 5.1±0.1 ug-O2/ml/hr of 1 day incubation to 27.4±0.3 ug-O2/ml/hr after 2-3 days. ETSA was highly maintained for 2 and 3 days even with the successive addition of the contaminated sediments to the bioreactor. The degradation rate of PAHs in the whole process was maintained between 81-95% regardless of inoculum size, 1/5 or 1/10. As a result, the degradation rate of PAHs could be maintained or even slightly increased when sediments were added after 2 days incubation with inoculum size higher than 10%. However, addition of cyclodextrin seems very critical. No significant degradation was observed and the inoculated bacteria were significantly reduced without cyclodextrin. The result implies that the fed-batch reactor could be applied to bioremediation of sediments contaminated by PAHs under appropriate conditions.