BACKGROUND: Biofloc technology is considered  a method that degrades organic waste by microorganisms and produces bacterial flocculation. OBJECTIVES: This study was performed to evaluate of the application of biofloc technology in therearing of common carp (Cyprinus carpio) fingerlings in intensive culture. METHODS: The experiment was designed in four treatments (Commercial diet as a control, 75% commercial diet + Biofloc, 50% commercial diet + Biofloc, 25% commercial diet + Biofloc) with carp fingerlings (Initial weight 58 ± .2 g) over a period of one month. Water exchange in Biofloc treatments was 1% during 24 h while water flow through system was used in control. At the end of experiment, all fish were intraperitoneally injected with 12×107 colony forming units (CFU) of Aeromonas hydrophila per fish. RESULTS:The results of the experiment indicated that the highest weight gain was observed in fingerlings fed 75% commercial diet + Biofloc that differed significantly from the group fed 25% commercial diet + Biofloc (p<0.05). There was no significant difference between control and 50% and 75% commercial diet as well (p<0.05). No significant difference was observed in case of condition factor, viscerosomatic index (VSI) and survival in experimental treatments (p>0.05). Also, Biofloc significantly increased ash content in muscle (p<0.05). The highest mortality (64.2 %) was observed in control inchallenge of Aeromonas hydrophila. CONCLUSIONS: The results suggest that the Biofloc technology can increase growth performances of carp fingerlings in intensive system and decrease water exchange via quality improvement.