There are provided a memory system and a method for operating the same. A memory system includes: a semiconductor memory device for outputting a ready/busy (R/B) signal by performing an internal operation in response to an operation command, and outputting status data by performing a status check operation in response to a status check command; and a controller for outputting the operation command and the status check command to the semiconductor memory device, and determining validity of the status data, based on the R/B signal.