An information recording medium, a method of recording and/or reproducing data to/from the medium, and a recording/reproducing apparatus using the medium, the medium having a data area including a user data area to record user data, and a spare area to record replacement blocks that replace defect blocks occurring in the user data area, wherein defect list entries include status information of the defect blocks and the replacement blocks, and the status information of the defect blocks in the user data area is changed, and the status information of the replacement blocks in the spare area is changed, in response to the spare area being newly allocated to re-initialize the medium.