Storage device and operating method thereof

A storage device for performing a read operation together with a program operation includes a memory device for storing data and a memory controller for controlling the memory device. The memory device includes an allow bit setting register for storing allow bits which are compared with fail bits included in read data read in a read operation and includes a read operation controller for controlling the memory device to immediately perform the read operation after a program operation. The memory controller includes a command generator for generating a command instructing the memory device to perform an operation, includes a bad block processor for setting a bad block, based on a result of the read operation performed by the memory device, and includes a fail information controller for setting an operation mode of a next read operation, based on the result of the read operation performed by the memory device.