Provided are a Peripheral Component Interconnect Express (PCIe) device and a method of operating the same. The PCIe device may include a performance analyzer, a delay time information generato and a command fetcher. The performance analyzer may measure throughputs of a plurality of functions, and generate throughput analysis information indicating a comparison result between the throughputs of the plurality of functions and throughput limits corresponding to the plurality of functions. The delay time information generator may generate a delay time for delaying a command fetch operation for each of the plurality of functions based on the throughput analysis information. The command fetcher may fetch a target command from a host based on a delay time of a function corresponding to the target command.